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-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/README.md32
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file1_Critical_Point_of_a_function.gifbin0 -> 8077401 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file1_Critical_Point_of_a_function.py77
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file2_Traces_and_Tangent.gifbin0 -> 2552938 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file2_Traces_and_Tangent.py88
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file3_Tangent_plane_at_extrema_of_a_function.gifbin0 -> 2198637 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file3_Tangent_plane_at_extrema_of_a_function.py73
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file4_Types_of_critical_points.gifbin0 -> 3864765 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file4_Types_of_critical_points.py134
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file5_f(x,y)=(y-x)(1-2x-3y).gifbin0 -> 1522415 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file5_f(x,y)=(y-x)(1-2x-3y).py29
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file1_Extrema_over_g(x,y)=k.gifbin0 -> 499796 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file1_Extrema_over_g(x,y)=k.py53
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-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file2_Geometric_Proof.py68
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file3_Optimizing_function_w.r.t_one_constraint.gifbin0 -> 2177236 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file3_Optimizing_function_w.r.t_one_constraint.py29
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-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file1_Tangent_Plane.py50
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file2_Tangent_plane_approximation_visualization.gifbin0 -> 946542 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file2_Tangent_plane_approximation_visualization.py74
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-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file3_Non_Differentiable_Function.py47
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file4_Tangent plane_at_extrema_and_saddle_point.gifbin0 -> 2513197 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file4_Tangent_plane_at_extrema_and_saddle_point.py62
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file1_Second_order_partial_derivatives.gifbin0 -> 3166332 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file1_Second_order_partial_derivatives.py78
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-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file2_Degenerate_Hessian_Matrix.py52
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file3_Nondegenerate_Hessian_Matrix.gifbin0 -> 8724439 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file3_Nondegenerate_Hessian_Matrix.py145
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file4_Contour_Diagram.gifbin0 -> 1150777 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file4_Contour_Diagram.py120
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file1_Visualization_of_dz.gifbin0 -> 558983 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file1_Visualization_of_dz.py53
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file2_Differentials.gifbin0 -> 576535 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file2_Differentials.py72
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file3_Total_differential_of_z.gifbin0 -> 732678 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file3_Total_differential_of_z.py91
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file4_total_differential_change.gifbin0 -> 300675 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file4_total_differential_change.py54
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file5_Total_differential_approximation.gifbin0 -> 423652 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file5_Total_differential_approximation.py48
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/README.md2
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_level_curves.gifbin245384 -> 0 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_level_curves2.gifbin893426 -> 0 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/Limits_and_Continuity_of_Multivariable_Function_Quiz.pdfbin0 -> 101435 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file1_epsilon_delta_defn.py120
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file2_limit_approach_point.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Limits and Continuity of Multivariable Functions/limit_approach_point.py)0
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file3_limit_func.py30
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file4_continuity_func.py32
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file1_epsilon_delta_defn.gifbin0 -> 214399 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file2_limit_approach_point.gif (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Limits and Continuity of Multivariable Functions/gifs/limit_approach_point.gif)bin47411 -> 47411 bytes
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-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file4_continuity_func.gifbin0 -> 523873 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/Multivariable_Functions_Quiz.pdf (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/Multivariable_Functions_Quiz.pdf)bin109631 -> 109631 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file1_multivariable_func_respresentation.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_respresntation.py)0
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file2_multivariable_func_examples.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_examples.py)0
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file3_plot_sphere.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_plot_sphere.py)0
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file4_vectorvf_sine.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_vectorvf_sine.py)0
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file5_derivative_vectorvf.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_derivative_vectorvf.py)0
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file1_multivariable_func_respresentation.gif (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_respresntation.gif)bin73055 -> 73055 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file2_multivariable_func_examples.gif (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_examples.gif)bin57945 -> 57945 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file3_plot_sphere.gif (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_plot_sphere.gif)bin198324 -> 198324 bytes
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-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/Scalar_Function_Quiz.pdf (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/Scalar_Function_Quiz.pdf)bin87455 -> 87455 bytes
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file1_domain_range.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_domain_range.py)0
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file2_scalar_function_application.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_application.py)0
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file3_parabola_example.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_parabola_example.py)0
-rw-r--r--FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file4_neural_nets.py (renamed from FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_neural_nets.py)0
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-rw-r--r--FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/README.md8
-rw-r--r--FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/file4_cube_surface.py195
-rw-r--r--FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/README.md12
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83 files changed, 2149 insertions, 22 deletions
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/README.md b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/README.md
new file mode 100644
index 0000000..5bd9cc5
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/README.md
@@ -0,0 +1,32 @@
+<h1><div align=”center”><b>SubTopic: Critical Points</b></h1></div>
+<br/></br>
+
+<tab>file1_Critical_Point_of_a_function
+
+![file1_Critical_Point_of_a_function](https://github.com/vnb09/FSF-mathematics-python-code-archive/blob/fsf_tasks/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file1_Critical_Point_of_a_function.gif?raw=true)
+<br/></br>
+<br/></br>
+
+<tab>file2_Traces_and_Tangent
+
+![file2_Traces_and_Tangent](https://github.com/vnb09/FSF-mathematics-python-code-archive/blob/fsf_tasks/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file2_Traces_and_Tangent.gif?raw=true)
+<br/></br>
+<br/></br>
+
+<tab>file3_Tangent_plane_at_extrema_of_a_function
+
+![file3_Tangent_plane_at_extrema_of_a_function](https://github.com/vnb09/FSF-mathematics-python-code-archive/blob/fsf_tasks/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file3_Tangent_plane_at_extrema_of_a_function.gif?raw=true)
+<br/></br>
+<br/></br>
+
+<tab>file4_Types_of_critical_points
+
+![file4_Types_of_critical_points](https://github.com/vnb09/FSF-mathematics-python-code-archive/blob/fsf_tasks/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file4_Types_of_critical_points.gif?raw=true)
+<br/></br>
+<br/></br>
+
+<tab>file5_f(x,y)=(y-x)(1-2x-3y)
+
+![file5_f(x,y)=(y-x)(1-2x-3y)](https://github.com/vnb09/FSF-mathematics-python-code-archive/blob/fsf_tasks/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file5_f(x%2Cy)%3D(y-x)(1-2x-3y).gif?raw=true)
+<br/></br>
+<br/></br>
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file1_Critical_Point_of_a_function.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file1_Critical_Point_of_a_function.gif
new file mode 100644
index 0000000..ca3989c
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file1_Critical_Point_of_a_function.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file1_Critical_Point_of_a_function.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file1_Critical_Point_of_a_function.py
new file mode 100644
index 0000000..e8cb08d
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file1_Critical_Point_of_a_function.py
@@ -0,0 +1,77 @@
+from manimlib.imports import*
+import math as m
+
+#---- case 1: parial derivatives exist at critical point of the function
+class firstScene(ThreeDScene):
+ def construct(self):
+
+ axes = ThreeDAxes()
+ label_x = TextMobject("$x$").shift([5.5,-0.5,0]) #---- x axis
+ label_y = TextMobject("$y$").shift([-0.5,5.5,0]).rotate(-4.5) #---- y axis
+
+ #---- f(x,y) = e^(-10x^2-10y^2)
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ m.exp(-10*u**2-10*v**2)
+ ]),u_min = -1, u_max = 1, v_min = -1, v_max = 1, checkerboard_colors = [TEAL_E,TEAL_D,TEAL_C,TEAL_B]).fade(0.6).scale(3.5).shift([0,0,1.5])
+
+ l1 = Line([0,0,3.75],[0,0,0],color = '#800000')
+
+ d = Dot([0,0,3.75],color = '#800000') #---- critical point
+
+ d_text = TextMobject("$\\frac{\\partial f}{\\partial x}=\\frac{\\partial f}{\\partial y} = 0$").scale(0.8).to_corner(UL)
+
+ f_text = TextMobject("Critical Point ",color = YELLOW).shift(3.4*UP).scale(0.5)
+
+ self.set_camera_orientation(phi = 45*DEGREES, theta = 40*DEGREES)
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.add_fixed_in_frame_mobjects(d_text)
+ self.begin_ambient_camera_rotation(rate = 0.2)
+ self.play(Write(surface))
+ self.wait(1)
+ self.play(Write(l1))
+ self.play(Write(d))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.wait(3)
+ self.play(FadeOut(f_text),FadeOut(surface),FadeOut(axes),FadeOut(d_text),FadeOut(d),FadeOut(l1),FadeOut(label_x),FadeOut(label_y))
+
+
+#---- case 2: parial derivatives do not exist at critical point of the function
+class secondScene(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+ label_x = TextMobject("$x$").shift([5.5,-0.5,0]) #---- x axis
+ label_y = TextMobject("$y$").shift([-0.5,5.5,0]).rotate(-4.5) #---- y axis
+
+ #---- g(x,y)= |x|+|y|
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ abs(u)+abs(v)
+ ]),u_min = -1.5, u_max = 1.5, v_min = -1.5, v_max = 1.5, checkerboard_colors = [TEAL_E,TEAL_D,TEAL_C,TEAL_B])
+
+ d2 = Dot([0,0,0],color = '#800000') #---- critical point
+
+ d2_text = TextMobject("$\\frac{\\partial f}{\\partial x}$ and/or $\\frac{\\partial f}{\\partial y}$ does not exist").scale(0.7).to_corner(UL)
+
+ g_text = TextMobject("Critical Point",color = YELLOW).shift(1.2*RIGHT).scale(0.6)
+
+ self.set_camera_orientation(phi = 60*DEGREES, theta = 40*DEGREES)
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.add_fixed_in_frame_mobjects(d2_text)
+ self.begin_ambient_camera_rotation(rate = 0.2)
+ self.wait(1)
+ self.play(Write(surface2))
+ self.wait(1)
+ self.play(Write(d2))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(g_text)
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file2_Traces_and_Tangent.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file2_Traces_and_Tangent.gif
new file mode 100644
index 0000000..84acf2e
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file2_Traces_and_Tangent.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file2_Traces_and_Tangent.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file2_Traces_and_Tangent.py
new file mode 100644
index 0000000..4b020e1
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file2_Traces_and_Tangent.py
@@ -0,0 +1,88 @@
+from manimlib.imports import*
+import math as m
+
+#---- tangent to the trace with x constant
+class firstScene(ThreeDScene):
+ def construct(self):
+
+ axes = ThreeDAxes().scale(1)
+ label_x = TextMobject("$x$").shift([5.8,-0.5,0])
+ label_y = TextMobject("$y$").shift([-0.5,-5.6,0]).rotate(-4.5)
+
+ #---- graph of f(x,y) = -x^2-y^2
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2-v**2
+ ]),u_min=-1,u_max=1, v_min=-1,v_max=1,checkerboard_colors=[PURPLE_C,PURPLE_D,PURPLE_E,PURPLE_B]).scale(1.5).shift([0,0,2]).rotate(0.2)
+
+ #---- curve(trace) along y axis
+ curve = ParametricSurface(
+ lambda u, v: np.array([
+ u*0.4,
+ v,
+ -v**2
+ ]),v_min =-1 , v_max =1 , u_min = -0.1, u_max = 0.1).scale(1.6).shift([0.02,0.1,2.3]).set_color("#800000").rotate(0.1)
+
+ d = Dot(color =YELLOW).shift([-0.05,-0.2,2.3]) #---- critical point
+
+ x_text = TextMobject("Tangent to the trace with $x$ constant at critical point").shift(3*RIGHT+2*UP).scale(0.5).to_corner(UL)
+
+ tangent_line = Line([-0.05,-1.5,2.3],[-0.05,1.5,2.3],color = '#228B22')
+
+ self.add(axes)
+ self.set_camera_orientation(phi = 40 * DEGREES, theta = 55 * DEGREES)
+ self.begin_ambient_camera_rotation(rate = 0.1)
+ self.add(label_x)
+ self.add(label_y)
+ self.play(Write(surface))
+ self.add_fixed_in_frame_mobjects(x_text)
+ self.add(curve)
+ self.wait(1)
+ self.play(Write(tangent_line),Write(d))
+ self.wait(1)
+
+
+
+#---- tangent to the trace with y constant
+class secondScene(ThreeDScene):
+ def construct(self):
+
+ axes = ThreeDAxes().scale(1)
+ label_x = TextMobject("$x$").shift([5.8,-0.5,0])
+ label_y = TextMobject("$y$").shift([-0.5,-5.6,0]).rotate(-4.5)
+
+ #---- graph of f(x,y) = -x^2-y^2
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2-v**2
+ ]),u_min = -1, u_max = 1, v_min = -1, v_max = 1, checkerboard_colors = [PURPLE_B,PURPLE_C,PURPLE_D,PURPLE_E]).scale(1.5).shift([0,0,2]).rotate(0.2)
+
+ #---- curve(trace) along x axis
+ curve = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v*0.4,
+ -u**2
+ ]),v_min = -0.1, v_max = 0.1, u_min = -1, u_max = 1).scale(1.6).shift([0.07,0.1,2.3]).set_color("#800000")
+
+ d = Dot(color = YELLOW).shift([0,-0.2,2.3]) #---- critical point
+
+ tangent_line = Line(color = '#228B22').scale(1).shift([0,-0.2,2.3]).rotate(m.radians(190),LEFT)
+
+ y_text = TextMobject("Tangent to the trace with $y$ constant at critical point").shift(3*RIGHT+2*UP).scale(0.5).to_corner(UL)
+
+ self.add(axes)
+ self.set_camera_orientation(phi = 40 * DEGREES, theta = 55 * DEGREES)
+ self.add(label_x)
+ self.add(label_y)
+ self.begin_ambient_camera_rotation(rate = 0.1)
+ self.play(Write(surface))
+ self.add_fixed_in_frame_mobjects(y_text)
+ self.add(curve)
+ self.wait(1.5)
+ self.play(Write(tangent_line),Write(d))
+ self.wait(0.5)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file3_Tangent_plane_at_extrema_of_a_function.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file3_Tangent_plane_at_extrema_of_a_function.gif
new file mode 100644
index 0000000..14fb318
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file3_Tangent_plane_at_extrema_of_a_function.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file3_Tangent_plane_at_extrema_of_a_function.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file3_Tangent_plane_at_extrema_of_a_function.py
new file mode 100644
index 0000000..e674113
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file3_Tangent_plane_at_extrema_of_a_function.py
@@ -0,0 +1,73 @@
+from manimlib.imports import*
+
+#---- tangent plane to minima of the function
+class firstScene(ThreeDScene):
+ def construct(self):
+
+ axes = ThreeDAxes()
+ label_x = TextMobject("$x$").shift([5.5,-0.5,0]) #---- x axis
+ label_y = TextMobject("$y$").shift([-0.5,5.5,0]).rotate(-4.5) #---- y axis
+
+ #---- parabola: f(x,y) = x**2 + y**2
+ parabola = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ u**2+v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [GREEN_E,GREEN_D,GREEN_C,GREEN_B], resolution = (20, 20)).scale(1)
+
+ d = Dot(np.array([0,0,0]), color = '#800000') # ---- critical point
+
+ tangent_plane = Rectangle(fill_color = '#C0C0C0', fill_opacity = 0.3).move_to(ORIGIN).fade(0.7) # ----tangent plane
+
+ parabola_text = TextMobject("Minimum with horizontal tangent plane").scale(0.7).to_corner(UL)
+
+ self.set_camera_orientation(phi = 75 * DEGREES, theta = 45 * DEGREES)
+ self.begin_ambient_camera_rotation(rate = 0.2)
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.add_fixed_in_frame_mobjects(parabola_text)
+ self.wait(1)
+ self.play(Write(parabola))
+ self.play(ShowCreation(d))
+ self.wait(1)
+ self.play(ShowCreation(tangent_plane))
+ self.wait(2)
+ self.play(FadeOut(parabola_text),FadeOut(parabola),FadeOut(tangent_plane),FadeOut(d),FadeOut(label_x),FadeOut(label_y),FadeOut(axes))
+
+
+#---- tangent plane to maxima of the function
+class secondScene(ThreeDScene):
+ def construct(self):
+
+ axes = ThreeDAxes()
+ label_x = TextMobject("$x$").shift([5.5,-0.5,0]) #---- x axis
+ label_y = TextMobject("$y$").shift([-0.5,5.5,0]).rotate(-4.5) #---- y axis
+
+ #----parabola: g(x,y) = -x**2-y**2
+ parabola = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2-v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [BLUE_E,BLUE_D,BLUE_C,BLUE_B], resolution = (20, 20)).scale(1)
+
+ d = Dot(np.array([0,0,0]), color = '#800000') #---- critical point
+
+ tangent_plane = Rectangle(fill_color = '#C0C0C0',fill_opacity = 0.3).move_to(ORIGIN).fade(0.7) #---- tangent plane
+
+ parabola_text = TextMobject("Maximum with horizontal tangent plane").scale(0.7).to_corner(UL)
+
+ self.set_camera_orientation(phi = 75 * DEGREES, theta = 45 * DEGREES)
+ self.begin_ambient_camera_rotation(rate = 0.2)
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.add_fixed_in_frame_mobjects(parabola_text)
+ self.wait(1)
+ self.play(Write(parabola))
+ self.play(ShowCreation(d))
+ self.wait(1)
+ self.play(ShowCreation(tangent_plane))
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file4_Types_of_critical_points.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file4_Types_of_critical_points.gif
new file mode 100644
index 0000000..91e7084
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file4_Types_of_critical_points.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file4_Types_of_critical_points.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file4_Types_of_critical_points.py
new file mode 100644
index 0000000..656fb68
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file4_Types_of_critical_points.py
@@ -0,0 +1,134 @@
+from manimlib.imports import*
+
+
+#---- Relative Maxima
+class firstScene(ThreeDScene):
+ def construct(self):
+
+ r_text = TextMobject("Relative Maximum at ORIGIN",color ='#87CEFA')
+
+ axes = ThreeDAxes()
+ label_x = TextMobject("$x$").shift([5.5,-0.5,0]) #---- x axis
+ label_y = TextMobject("$y$").shift([-0.5,5.5,0]).rotate(-4.5) #---- y axis
+
+ #----graph of the function f(x,y) = -x**2-y**2
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2-v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [YELLOW_B,YELLOW_C,YELLOW_D, YELLOW_E]).scale(1.5).shift([0,0,-0.51]).fade(0.3)
+
+ f_text = TextMobject("$f(x,y) = -x^2-y^2$").to_corner(UL)
+
+ d = Dot(color = "#800000").shift([0,0,0]) #---- critical point
+
+ self.set_camera_orientation(phi = 75 * DEGREES, theta = 45 * DEGREES)
+ self.add_fixed_in_frame_mobjects(r_text)
+ self.wait(1)
+ self.play(FadeOut(r_text))
+ self.begin_ambient_camera_rotation(rate = 0.1)
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.play(Write(surface),Write(d))
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.wait(2)
+ self.play(FadeOut(axes),FadeOut(surface),FadeOut(f_text),FadeOut(d),FadeOut(label_x),FadeOut(label_y))
+
+
+#---- Relative Minima
+class secondScene(ThreeDScene):
+ def construct(self):
+
+ r2_text = TextMobject("Relative Minimum at ORIGIN",color ='#87CEFA')
+
+ axes = ThreeDAxes()
+ label_x = TextMobject("$x$").shift([5.5,-0.5,0]) #---- x axis
+ label_y = TextMobject("$y$").shift([-0.5,5.5,0]).rotate(-4.5) #---- y axis
+
+ #----graph of the function g(x,y) = x**2+y**2
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ u**2+v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors =[TEAL_B,TEAL_C,TEAL_D,TEAL_E]).scale(1.5).shift([0,0,0.55]).fade(0.1)
+
+ d = Dot(color = "#800000").shift([0,0,0]) #---- critical point
+
+ g_text = TextMobject("$f(x,y) = x^2+y^2$").to_corner(UL)
+
+ self.set_camera_orientation(phi = 75 * DEGREES, theta = 45 * DEGREES)
+ self.add_fixed_in_frame_mobjects(r2_text)
+ self.wait(1)
+ self.play(FadeOut(r2_text))
+ self.begin_ambient_camera_rotation(rate = 0.1)
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.play(Write(surface),Write(d))
+ self.add_fixed_in_frame_mobjects(g_text)
+ self.wait(2)
+ self.play(FadeOut(axes),FadeOut(surface),FadeOut(g_text),FadeOut(d),FadeOut(label_x),FadeOut(label_y))
+
+
+
+#---- Saddle Point
+class thirdScene(ThreeDScene):
+ def construct(self):
+
+ r3_text = TextMobject("Saddle Point", color = '#87CEFA')
+
+ axes = ThreeDAxes()
+ label_x = TextMobject("$x$").shift([5.5,-0.5,0]) #---- x axis
+ label_y = TextMobject("$y$").shift([-0.5,5.5,0]).rotate(-4.5) #---- y axis
+
+ #---- graph of function h(x,y) = -x^2 + y^2
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2+v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1,checkerboard_colors = [PURPLE_B,PURPLE_C,PURPLE_D,PURPLE_E]).scale(1.5).shift([0,0,0])
+
+ #---- curve(trace) along x axis
+ curve_x = ParametricSurface(
+ lambda u, v: np.array([
+ u*0.4,
+ v,
+ v**2
+ ]),v_min = -1, v_max = 1, u_min = -0.2, u_max = 0.2).shift([0,0,0.34]).scale(1.5).set_color("#800000")
+
+ #---- curve(trace) along y axis
+ curve_y = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v*0.4,
+ -u**2
+ ]),v_min = -0.2, v_max = 0.2, u_min = -1, u_max = 1).scale(1.6).shift([0,0,-0.1]).set_color("#800000")
+
+ d = Dot(color = GREEN).shift([0,0,0.1]) #---- critical point
+
+ h_text = TextMobject("$f(x,y) = -x^2+y^2$").to_corner(UL)
+
+ self.add_fixed_in_frame_mobjects(r3_text)
+ self.wait(1)
+ self.set_camera_orientation(phi = 50 * DEGREES,theta = 45 * DEGREES)
+ self.play(FadeOut(r3_text))
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.begin_ambient_camera_rotation(rate = 0.3)
+ self.add_fixed_in_frame_mobjects(h_text)
+ self.play(Write(surface))
+ self.wait(1)
+ self.add(curve_y)
+ self.add(d)
+ self.wait(1)
+ self.play(FadeOut(curve_y))
+ self.wait(1)
+ self.add(curve_x)
+ self.wait(1)
+ self.add(d)
+ self.wait(1)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file5_f(x,y)=(y-x)(1-2x-3y).gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file5_f(x,y)=(y-x)(1-2x-3y).gif
new file mode 100644
index 0000000..4bc92f8
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file5_f(x,y)=(y-x)(1-2x-3y).gif
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diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file5_f(x,y)=(y-x)(1-2x-3y).py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file5_f(x,y)=(y-x)(1-2x-3y).py
new file mode 100644
index 0000000..41c3b61
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file5_f(x,y)=(y-x)(1-2x-3y).py
@@ -0,0 +1,29 @@
+from manimlib.imports import*
+
+#---- visualization of the function
+class ExampleAnimation(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+ label_x = TextMobject("$x$").shift([5.5,-0.5,0]) #---- x axis
+ label_y = TextMobject("$y$").shift([-0.5,5.5,0]).rotate(-4.5) #---- y axis
+
+ #---- f(x,y) = (y-x)(1-2x-3y)
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ (v-u)*(1-2*u-3*v)
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [PURPLE_B,PURPLE_C,PURPLE_D, PURPLE_E]).scale(1).fade(0.2).shift([0.2,0.2,0])
+
+ f_text = TextMobject("$f(x,y) = (y-x)(1-2x-3y)$").to_corner(UL)
+
+ self.set_camera_orientation(phi = 60 * DEGREES, theta = 75 * DEGREES)
+ self.begin_ambient_camera_rotation(rate=0.1)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.wait(1)
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.wait(1)
+ self.play(Write(f))
+ self.wait(4)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file1_Extrema_over_g(x,y)=k.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file1_Extrema_over_g(x,y)=k.gif
new file mode 100644
index 0000000..1e1782e
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file1_Extrema_over_g(x,y)=k.gif
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diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file1_Extrema_over_g(x,y)=k.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file1_Extrema_over_g(x,y)=k.py
new file mode 100644
index 0000000..17f31ac
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file1_Extrema_over_g(x,y)=k.py
@@ -0,0 +1,53 @@
+from manimlib.imports import*
+
+class firstScene(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ u**2+v**2+u**3-v**3
+ ]),u_min=-0.5,u_max=0.5, v_min=-0.5,v_max=0.5).scale(5).shift([0,1,2.5]).set_color('#F0FFFF').fade(0.4)
+
+ c = Circle().set_color('#FF00FF').shift([-0.4,0,1.5]).rotate(1.9,UP).scale(0.7)
+
+ minima = Dot(color = '#4169E1').shift([-0.5,0.5,1]).rotate(1.571,UP)
+ maxima = Dot(color = '#4169E1').shift([0.1,0,2.2]).rotate(1.571,UP)
+
+ l1 = DashedLine([-0.5,0.5,0.9],[-0.5,0.5,0],color = '#F08080')
+ l2 = DashedLine([0.1,0,2.1],[0.1,0,0],color = '#F08080')
+
+ c2 = Circle(fill_opacity= 0.5).shift([-0.3,0.2,0]).scale(0.4)
+
+ minima_refl = Dot(color = '#4682B4').shift([-0.5,0.5,0]).rotate(1.571,UP)
+ maxima_refl = Dot(color = '#4682B4').shift([0.1,0,0]).rotate(1.571,UP)
+
+ max_text = TextMobject("maximum over $g(x,y)=k$",color = '#FFA074').shift([-1.7,0,0]).scale(0.5).shift(2.2*UP)
+ min_text = TextMobject("minimum over $g(x,y)=k$",color = '#FFA074').shift([2.5,0.5,1]).scale(0.5).shift(0.5*UP)
+ label_f = TextMobject("$z=f(x,y)$",color = '#8A2BE2').scale(0.5).shift(3*UP+3*RIGHT)
+ label_g = TextMobject("$g(x,y)=k$",color = '#8A2BE2').scale(0.5).shift(2*RIGHT)
+
+
+ self.add(axes)
+ self.set_camera_orientation(phi=75*DEGREES,theta=45*DEGREES)
+ self.play(Write(surface))
+ self.add_fixed_in_frame_mobjects(label_f)
+ self.wait(2)
+ self.play(Write(c))
+ self.wait(1)
+ self.play(Write(maxima))
+ self.add_fixed_in_frame_mobjects(max_text)
+ self.wait(1)
+ self.play(Write(minima))
+ self.add_fixed_in_frame_mobjects(min_text)
+ self.wait(1)
+ self.play(ShowCreation(l1),ShowCreation(l2))
+ self.play(Write(c2))
+ self.add_fixed_in_frame_mobjects(label_g)
+ self.wait(1)
+ self.play(Write(maxima_refl))
+ self.play(Write(minima_refl))
+ self.wait(1)
+
+
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file2_Geometric_Proof.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file2_Geometric_Proof.gif
new file mode 100644
index 0000000..b22afb3
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file2_Geometric_Proof.gif
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diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file2_Geometric_Proof.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file2_Geometric_Proof.py
new file mode 100644
index 0000000..4374ff7
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file2_Geometric_Proof.py
@@ -0,0 +1,68 @@
+from manimlib.imports import*
+
+class firstScene(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes().scale(0.7).rotate(math.radians(180))
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ 1*np.sin(u)*np.cos(v),
+ 1*np.sin(u)*np.sin(v),
+ -1*np.sin(u)*np.sin(u)+2
+ ]),u_min=0,u_max=PI/2,v_min=0,v_max=2*PI,checkerboard_colors=[GREEN_C, GREEN_E]).scale(1).shift([-1.5,-1.5,0])
+
+ d = Dot([-2,-2.55,0],color = '#800000')
+ a_df = Arrow(color = '#00FFFF').rotate(-2).shift(3.2*DOWN+2.3*LEFT) #---- f parallel to g
+ a_dg = Arrow(color = '#FF00FF').scale(0.8).shift(3.2*DOWN+2.3*LEFT).rotate(-2) #---- f parallel to g
+
+ b_df = Arrow(color = '#00FFFF').rotate(1.1).shift(0.82*LEFT+0.15*UP) #---- f parallel to g
+ b_dg = Arrow(color = '#FF00FF').scale(0.6).rotate(-2).shift(1.43*LEFT+1.1*DOWN) #---- f parallel to g
+
+
+ qd = Dot(color = '#800000').shift(1.2*LEFT+0.6*DOWN)
+
+ l1 = Line([-1,-3.1,0],[-4,-3.1,0],color = PINK).rotate(-0.3).fade(0.6)
+ l2 = Line([-0.9,-2.9,0],[-4,-2.9,0],color = PINK).rotate(-0.3).fade(0.6)
+ l3= Line([-0.8,-2.7,0],[-4,-2.7,0],color = PINK).rotate(-0.3).fade(0.6)
+ l4= Line([-0.7,-2.45,0],[-4,-2.45,0],color = PINK).rotate(-0.3).fade(0.6)
+ l5= Line([-0.6,-2.2,0],[-4,-2.25,0],color = PINK).rotate(-0.3).fade(0.6)
+ l6 = Line([-0.5,-2,0],[-4,-2,0],color = PINK).rotate(-0.3).fade(0.6)
+ l7 = Line([-0.4,-1.8,0],[-4,-1.8,0],color = PINK).rotate(-0.3).fade(0.6)
+ l8 = Line([-0.3,-1.6,0],[-4,-1.6,0],color = PINK).rotate(-0.3).fade(0.6)
+ l9= Line([-0.2,-1.4,0],[-4,-1.4,0],color = PINK).rotate(-0.3).fade(0.6)
+ l10= Line([-0.1,-1.2,0],[-4,-1.2,0],color = PINK).rotate(-0.3).fade(0.6)
+ l11 = Line([-0,-1,0],[-4,-1,0],color = PINK).rotate(-0.3).fade(0.6)
+ l12 = Line([-0,-0.8,0],[-4,-0.8,0],color = PINK).rotate(-0.3).fade(0.6)
+ l13= Line([-0,-0.55,0],[-4,-0.55,0],color = PINK).rotate(-0.3).fade(0.6)
+ l14= Line([-0,-0.35,0],[-4,-0.35,0],color = PINK).rotate(-0.3).fade(0.6)
+ l15= Line([-0.,-0.15,0],[-4,-0.15,0],color = PINK).rotate(-0.3).fade(0.6)
+
+ level_Curve = VGroup(l1,l2,l3,l4,l5,l6,l7,l8,l9,l10,l11,l12,l13,l14,l15)
+
+ rel_text = TextMobject("$\\nabla f = \\lambda \\nabla g$",color = TEAL).shift([3,3.2,0]).scale(0.5)
+
+ f_text = TextMobject("$\\nabla f$",color = '#800000').shift([1,1,0]).scale(0.5)
+ g_text = TextMobject("$\\nabla g$").shift([1.2,-0.8,0]).scale(0.5)
+
+ p_text= TextMobject("$P$").shift([1.8,2.6,0]).scale(0.5)
+
+
+
+ self.add(axes)
+ self.set_camera_orientation(phi=0 * DEGREES, theta = 90*DEGREES)
+ self.play(Write(surface))
+ self.wait(1)
+ self.play(ShowCreation(level_Curve))
+ self.wait(1)
+ self.play(ShowCreation(a_df),ShowCreation(a_dg),Write(d))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(rel_text)
+ self.add_fixed_in_frame_mobjects(p_text)
+ self.wait(1)
+ self.play(Write(qd))
+ self.wait(1)
+ self.play(ShowCreation(b_df))
+ self.play(ShowCreation(b_dg))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.add_fixed_in_frame_mobjects(g_text)
+ self.wait(1)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file3_Optimizing_function_w.r.t_one_constraint.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file3_Optimizing_function_w.r.t_one_constraint.gif
new file mode 100644
index 0000000..9602283
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file3_Optimizing_function_w.r.t_one_constraint.gif
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diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file3_Optimizing_function_w.r.t_one_constraint.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file3_Optimizing_function_w.r.t_one_constraint.py
new file mode 100644
index 0000000..bf75dd8
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Lagrange-Multipliers/file3_Optimizing_function_w.r.t_one_constraint.py
@@ -0,0 +1,29 @@
+from manimlib.imports import*
+
+class firstScene(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+ cylinder = ParametricSurface(
+ lambda u, v: np.array([
+ np.cos(TAU * v),
+ np.sin(TAU * v),
+ 2 * (u)
+ ]),checkerboard_colors=[YELLOW_C,YELLOW_D,YELLOW_E]
+ ).fade(0.4) #Resolution of the surfaces
+
+ plane = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ u+v
+ ]),checkerboard_colors=[TEAL_C,TEAL_D,TEAL_E]
+ ).scale(2.5)
+ self.add(axes)
+ self.set_camera_orientation(phi=75*DEGREES,theta=45*DEGREES)
+ self.play(Write(cylinder))
+ self.play(Write(plane))
+ self.wait(1)
+ self.begin_ambient_camera_rotation(rate=0.7)
+ self.wait(5)
+ self.move_camera(phi=35*DEGREES,theta=-45*DEGREES)
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file1_Tangent_Plane.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file1_Tangent_Plane.gif
new file mode 100644
index 0000000..2b8bf5f
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file1_Tangent_Plane.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file1_Tangent_Plane.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file1_Tangent_Plane.py
new file mode 100644
index 0000000..4c17f90
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file1_Tangent_Plane.py
@@ -0,0 +1,50 @@
+from manimlib.imports import*
+
+#---- tangent plane is parallel to the surface of the funtion at a point
+class firstScene(ThreeDScene):
+ def construct(self):
+
+ s1_text=TextMobject("Suppose, the point $(x,y)$ lies on the surface of the function.").scale(0.5).shift(2*UP)
+ s2_text=TextMobject("When zooming on that point, the surface would appear more and more like a plane.").scale(0.5).shift(1*UP)
+ s3_text=TextMobject("This plane is called the tangent plane.").scale(0.5)
+
+ #---- graph of function f(x,y) = -x^2-y^2
+
+ f = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2-v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [YELLOW_B,YELLOW_C,YELLOW_D, YELLOW_E]).shift([0,0,0]).scale(1)
+
+
+ d = Dot([0,0,0],color = '#800000') #---- critical point
+
+ r = Rectangle(color = PURPLE,fill_opacity=0.2).shift([0.1,0,0]).scale(0.3) #---- tangent plane
+
+ s = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2-v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [YELLOW_B,YELLOW_C,YELLOW_D, YELLOW_E]).shift([0,0,0]).scale(3.5)
+
+ d2 = Dot([0,0,2.5],color = '#800000') #---- changing position of critical point
+
+ r2 = Rectangle(color = PURPLE,fill_opacity=0.5).shift([0.1,0,2.5]).scale(0.3) #---- changing position of tangent plane
+
+ self.set_camera_orientation(phi = 50 * DEGREES, theta = 45 * DEGREES)
+ self.add_fixed_in_frame_mobjects(s1_text)
+ self.add_fixed_in_frame_mobjects(s2_text)
+ self.add_fixed_in_frame_mobjects(s3_text)
+ self.wait(2)
+ self.play(FadeOut(s1_text))
+ self.play(FadeOut(s2_text))
+ self.play(FadeOut(s3_text))
+ self.wait(1)
+ self.play(Write(f))
+ self.play(Write(d))
+ self.play(Write(r))
+ self.wait(2)
+ self.play(ReplacementTransform(f,s),ReplacementTransform(d,d2),ReplacementTransform(r,r2))
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file2_Tangent_plane_approximation_visualization.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file2_Tangent_plane_approximation_visualization.gif
new file mode 100644
index 0000000..d23405d
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file2_Tangent_plane_approximation_visualization.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file2_Tangent_plane_approximation_visualization.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file2_Tangent_plane_approximation_visualization.py
new file mode 100644
index 0000000..d1ecf8c
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file2_Tangent_plane_approximation_visualization.py
@@ -0,0 +1,74 @@
+from manimlib.imports import*
+
+#---- tangent plane is parallel to the x-y plane
+class MaximaScene(ThreeDScene):
+ def construct(self):
+
+ axes = ThreeDAxes().scale(1.2)
+ label_x= TextMobject("$x$").shift([5.4,-0.5,0]) #---- x axis
+ label_y= TextMobject("$y$").shift([-0.5,5.2,0]).rotate(-4.5) #---- y axis
+
+ #---- graph of the function
+ s = ParametricSurface(
+ lambda u, v: np.array([
+ 1.5*np.cos(u)*np.cos(v),
+ 1.5*np.cos(u)*np.sin(v),
+ 1.5*np.sin(u)
+ ]),u_min=0,u_max=PI,v_min=PI,v_max=2*PI,checkerboard_colors=[BLUE_B,BLUE_C,BLUE_D,BLUE_E]).scale(1.5).shift([-0.8,0.5,1.5])
+
+ d1 = Dot([0.2,2.01,2.24],color = '#800000').rotate(1.1,LEFT) #---- point(x_0,y_0)
+ d1_copy = Dot([1.1,2.2,-0.45],color = '#800000') #---- projection of point(x_0,y_0) on x-y plane
+ d1_text = TextMobject("$(x_0,y_0)$",color = "#8B0000").scale(0.4).shift(1.3*RIGHT+1.1*UP)
+
+ d2 = Dot([1.1,2.2,2.7],color = '#800000').rotate(1,LEFT) #---- point(x,y)
+ d2_copy = Dot([0.1,1.95,0.4],color = '#800000') #---- projection of point(x,y) on x-y plane
+ d2_text = TextMobject("$(x,y)$",color = "#8B0000").scale(0.4).shift(0.6*RIGHT+0.8*UP)
+
+ t_plane = Rectangle(color = PURPLE, fill_opacity=0.3).scale(0.4).rotate(1,LEFT).shift([1.1,2.5,2.9]) #---- tangent plane
+
+ t_text= TextMobject("Tangent Plane",color = RED).scale(0.5).shift(0.3*RIGHT+1.3*UP).rotate(math.radians(5),LEFT)
+
+ l1 = Line([1.1,2.2,2.6],[1.1,2.2,-0.45]).fade(0.2)
+ l2 = Line([0.1,1.95,2.05],[0.1,1.95,0.4]).fade(0.2)
+
+ a1 = Line([0.1,1.95,0.4],[1.1,2.2,-0.45],color ="#00FF7F")
+ a_x = Line([0.1,1.95,0.4],[1.7,1.95,0.4],color ="#9400D3")
+ a_y = Line([0.1,1.95,0.4],[0.1,2.75,0.4],color ="#8B4513")
+ a2 = Line([1.7,1.95,0.4],[1.7,2.75,0.4])
+ a3 = Line([0.1,2.75,0.4],[1.7,2.75,0.4])
+
+ #---- transition of tangent plane
+
+ t2_plane = Rectangle(color = PURPLE, fill_opacity=0.3).scale(0.4).rotate(1,LEFT).shift([1.1,2.5,2])
+ t3_plane = Rectangle(color = PURPLE, fill_opacity=0.3).scale(0.4).rotate(math.radians(180),LEFT).shift([1.1,2.5,2])
+ t4_plane = Rectangle(color = PURPLE, fill_opacity=0.3).scale(0.4).rotate(math.radians(180),LEFT).shift([0.9,2.35,0.4])
+
+ #-------------------------------------------
+ self.set_camera_orientation(phi = 50 * DEGREES, theta = 45 * DEGREES)
+ self.wait(1)
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.play(Write(s))
+ self.wait(1)
+ self.play(Write(d1))
+ self.add_fixed_in_frame_mobjects(d1_text)
+ self.play(ShowCreation(t_plane))
+ self.add_fixed_in_frame_mobjects(t_text)
+ self.wait(1)
+ self.play(FadeOut(t_text),Write(d2))
+ self.add_fixed_in_frame_mobjects(d2_text)
+ self.wait(1)
+ self.play(Write(l1),Write(l2))
+ self.play(Write(d2_copy),Write(d1_copy))
+ self.wait(1)
+ self.play(Write(a1),Write(a_x),Write(a_y))
+ self.wait(1)
+ self.play(Write(a2),Write(a3))
+ self.wait(1)
+ self.play(ReplacementTransform(t_plane,t2_plane))
+ self.wait(1)
+ self.play(ReplacementTransform(t2_plane,t3_plane))
+ self.wait(1)
+ self.play(ReplacementTransform(t3_plane,t4_plane))
+ self.wait(1)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file3_Non_Differentiable_Function.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file3_Non_Differentiable_Function.gif
new file mode 100644
index 0000000..7581a33
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file3_Non_Differentiable_Function.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file3_Non_Differentiable_Function.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file3_Non_Differentiable_Function.py
new file mode 100644
index 0000000..79d0948
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file3_Non_Differentiable_Function.py
@@ -0,0 +1,47 @@
+from manimlib.imports import*
+import math
+
+#---- tangent plane does not exists for f(x,y): sqrt(x**2+y**2) at origin
+
+class TangenttoSurface(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes().rotate(2.3)
+ axes2 = ThreeDAxes().scale(2).rotate(2.3).shift([0,0,1.3])
+
+ #----f(x,y): sqrt(x**2+y**2)
+ p = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -math.sqrt(u**2+v**2)
+ ]),v_min = -1,v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [RED_C,TEAL_D],
+ resolution = (20, 20)).scale(1)
+
+ #----size increased of f(x,y): sqrt(x**2+y**2)
+ p2 = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -math.sqrt(u**2+v**2)
+ ]),v_min = -1,v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [RED_C,TEAL_D],
+ resolution = (20, 20)).scale(3).shift([0,0,0])
+
+ self.set_camera_orientation(phi = 75 * DEGREES,theta = 40*DEGREES)
+
+ d = Dot([0,0,0],color = '#800000') #---- critical point
+ d2 = Dot([0,0,1.5],color = '#800000').scale(2) #---- size increased of critical point
+
+ f_text = TextMobject("$f$ is not differentiable at origin,because the surface").scale(0.5).to_corner(UL)
+ f2_text = TextMobject("is not flat when zoomed in at the origin.").scale(0.5).to_corner(UL).shift(0.5*DOWN)
+
+ self.add(axes)
+ self.wait(1)
+ self.play(Write(p),Write(d))
+ self.wait(1)
+ self.move_camera(phi = 50 * DEGREES,theta = 40*DEGREES)
+ self.wait(1)
+ self.play(ReplacementTransform(axes,axes2),ReplacementTransform(p,p2),ReplacementTransform(d,d2))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.add_fixed_in_frame_mobjects(f2_text)
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file4_Tangent plane_at_extrema_and_saddle_point.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file4_Tangent plane_at_extrema_and_saddle_point.gif
new file mode 100644
index 0000000..cfe054b
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file4_Tangent plane_at_extrema_and_saddle_point.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file4_Tangent_plane_at_extrema_and_saddle_point.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file4_Tangent_plane_at_extrema_and_saddle_point.py
new file mode 100644
index 0000000..d129213
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Tangent-Plane-Approximations/file4_Tangent_plane_at_extrema_and_saddle_point.py
@@ -0,0 +1,62 @@
+from manimlib.imports import*
+
+class TangenttoSurface(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+
+ #----graph of first function f(x,y) = -x**2-y**2
+ f = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2-v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [YELLOW_D, YELLOW_E],
+ resolution = (20, 20)).scale(1)
+ f_text = TextMobject("Tangent plane at relative maxima").to_corner(UL).scale(0.5)
+
+ #----graph of second function f(x,y) = -x**2+y**2
+ f2 = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2+v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [RED_D, RED_E],
+ resolution = (20, 20)).scale(1)
+ f2_text = TextMobject("Tangent plane at saddle point").to_corner(UL).scale(0.5)
+
+ #----graph of third function f(x,y) = x**2+y**2
+ f3 = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ u**2+v**2
+ ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [GREEN_D, GREEN_E],
+ resolution = (20, 20)).scale(1)
+ f3_text = TextMobject("Tangent plane at relative minima").to_corner(UL).scale(0.5)
+
+ self.set_camera_orientation(phi = 75 * DEGREES, theta = -45 * DEGREES )
+ d = Dot(np.array([0,0,0]), color = '#800000') #---- critical point
+
+ r = Rectangle(height = 2,breadth = 1,color = PURPLE).scale(0.5)
+
+ self.begin_ambient_camera_rotation(rate = 0.3)
+ self.add(axes)
+ self.play(Write(f),Write(d))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.play(ShowCreation(r))
+ self.wait(1)
+ self.play(FadeOut(r),FadeOut(f),FadeOut(d),FadeOut(f_text))
+ self.wait(1)
+ self.play(Write(f2),Write(d))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(f2_text)
+ self.play(ShowCreation(r))
+ self.wait(1)
+ self.play(FadeOut(r),FadeOut(f2),FadeOut(d),FadeOut(f2_text))
+ self.wait(1)
+ self.play(Write(f3),Write(d))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(f3_text)
+ self.play(ShowCreation(r))
+ self.wait(1)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file1_Second_order_partial_derivatives.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file1_Second_order_partial_derivatives.gif
new file mode 100644
index 0000000..3471e4d
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file1_Second_order_partial_derivatives.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file1_Second_order_partial_derivatives.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file1_Second_order_partial_derivatives.py
new file mode 100644
index 0000000..84052cc
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file1_Second_order_partial_derivatives.py
@@ -0,0 +1,78 @@
+from manimlib.imports import*
+
+#---- graphs of second-order partial derivatives of a function
+class SurfacesAnimation(ThreeDScene):
+ def construct(self):
+
+ axes = ThreeDAxes()
+ x_label = TextMobject('$x$').shift([5,0.5,0]) #---- x axis
+ y_label = TextMobject('$y$').shift([0.5,4,0]).rotate(-4.5) #---- y axis
+
+ #---- surface of function: f(x,y) = (x^2+y^2)^2
+ surface_f = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ ((u**2)+(v**2))**2
+ ]),v_min=-1,v_max=1,u_min=-1,u_max=1,checkerboard_colors=[GREEN_D, GREEN_E]).scale(1)
+
+ #---- surface of second-order partial derivative f_xx
+ surface_fxx = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ (3*u**2)+(v**2)
+ ]),v_min=-1,v_max=1,u_min=-1,u_max=1,checkerboard_colors=[YELLOW_D, YELLOW_E]).shift([0,0,0]).scale(0.6)
+
+ #---- surface of second-order partial derivative f_yy
+ surface_fyy = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ (u**2)+(3*v**2)
+ ]),v_min=-1,v_max=1,u_min=-1,u_max=1,checkerboard_colors=[PURPLE_D, PURPLE_E]).scale(0.6).shift([0,0,0])
+
+ #---- surface of second-order partial derivative f_xy = f_yx
+ surface_fxy = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ 8*u*v
+ ]),v_min=-1,v_max=1,u_min=-1,u_max=1,checkerboard_colors=[TEAL_D, TEAL_E]).scale(0.6)
+
+ f_text= TextMobject("$f(x,y) = (x^2+y^2)^2$",color = GREEN).scale(0.7).to_corner(UL)
+
+ fxx_text= TextMobject("$f_{xx} = 12x^2+4y^2$ (Concavity along x axis)",color = YELLOW).scale(0.5).to_corner(UL)
+
+ fyy_text= TextMobject("$f_{yy} = 4x^2+12y^2$(Concavity along y axis)",color = PURPLE).scale(0.5).to_corner(UL)
+
+ fxy_text= TextMobject("$f_{xy} = f_{yx} = 8xy$ (Twisting of the function)",color = TEAL).scale(0.5).to_corner(UL)
+
+
+ self.set_camera_orientation(phi = 40 * DEGREES, theta = 45 * DEGREES)
+ self.begin_ambient_camera_rotation(rate = 0.1)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.add(axes)
+ self.add(x_label)
+ self.add(y_label)
+ self.wait(1)
+ self.play(Write(surface_f))
+ self.wait(2)
+ self.play(FadeOut(f_text))
+
+
+ self.play(ReplacementTransform(surface_f,surface_fxx))
+
+ self.add_fixed_in_frame_mobjects(fxx_text)
+ self.wait(2)
+ self.play(FadeOut(fxx_text))
+
+ self.play(ReplacementTransform(surface_fxx,surface_fyy))
+ self.add_fixed_in_frame_mobjects(fyy_text)
+ self.wait(2)
+ self.play(FadeOut(fyy_text))
+
+ self.play(ReplacementTransform(surface_fyy,surface_fxy))
+ self.move_camera(phi = 35 * DEGREES, theta = 80 * DEGREES)
+ self.add_fixed_in_frame_mobjects(fxy_text)
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file2_Degenerate_Hessian_Matrix.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file2_Degenerate_Hessian_Matrix.gif
new file mode 100644
index 0000000..d49cdd5
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file2_Degenerate_Hessian_Matrix.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file2_Degenerate_Hessian_Matrix.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file2_Degenerate_Hessian_Matrix.py
new file mode 100644
index 0000000..c1e3516
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file2_Degenerate_Hessian_Matrix.py
@@ -0,0 +1,52 @@
+from manimlib.imports import*
+
+class firstscene(Scene):
+ def construct(self):
+
+ h_text = TextMobject("Degenerate Hessian Matrix", color = RED).scale(1).shift(UP)
+
+
+ f_text = TextMobject("$f(x,y) = 2x^3+y^3$", color = TEAL).scale(1).to_corner(UL)
+ c_text = TextMobject("Critical Point: $(0,0)$", color = TEAL).scale(1).next_to(f_text).shift(DOWN+4.3*LEFT)
+ m_text = TextMobject("\\begin{equation*} D_2(x,y)= \\begin{vmatrix} 12x\\space & 0\\space \\\\ 0 & 6y \\end{vmatrix} \\end{equation*}",color = YELLOW)
+ d_text = TextMobject("\\begin{equation*} D_2(0,0)= \\begin{vmatrix} 0 \\space & 0\\space \\\\ 0 & 0 \\end{vmatrix} \\end{equation*}",color = PURPLE)
+
+
+ t_text = TextMobject("$D_2 = 0$(Inconclusive)", color = TEAL).scale(1).shift(2*DOWN)
+
+ self.play(ShowCreation(h_text))
+ self.wait(1)
+ self.play(FadeOut(h_text))
+ self.wait(1)
+ self.play(ShowCreation(f_text))
+ self.wait(1)
+ self.play(ShowCreation(c_text))
+ self.wait(1)
+ self.play(ShowCreation(m_text))
+ self.wait(2)
+ self.play(ReplacementTransform(m_text,d_text))
+ self.wait(1)
+ self.play(ShowCreation(t_text))
+ self.wait(2)
+
+
+class SecondScene(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+
+ f = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ (2*u**3)+v**3
+ ]),v_min=-1,v_max=1,u_min=-1,u_max=1,checkerboard_colors=[TEAL_C,YELLOW_D,BLUE_E],
+ resolution=(20, 20)).scale(1)
+
+ self.set_camera_orientation(phi=25 * DEGREES,theta = 80*DEGREES)
+ self.begin_ambient_camera_rotation(rate=0.1)
+
+ f_text = TextMobject("$f(x,y) = 2x^3+y^3$",color = ORANGE).shift(2*DOWN+2*RIGHT).scale(0.8)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.add(axes)
+ self.play(Write(f))
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file3_Nondegenerate_Hessian_Matrix.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file3_Nondegenerate_Hessian_Matrix.gif
new file mode 100644
index 0000000..2b0acb3
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file3_Nondegenerate_Hessian_Matrix.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file3_Nondegenerate_Hessian_Matrix.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file3_Nondegenerate_Hessian_Matrix.py
new file mode 100644
index 0000000..3056842
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file3_Nondegenerate_Hessian_Matrix.py
@@ -0,0 +1,145 @@
+from manimlib.imports import*
+
+class firstScene(Scene):
+ def construct(self):
+
+ e_text = TextMobject("Case 3: One positive and one negative eigenvalue", color = YELLOW).scale(1).shift(3*UP+1*LEFT)
+ f_text = TextMobject("$f(x,y) = x^2-2y^2-2x$").scale(0.8).next_to(e_text).shift(6*LEFT+DOWN)
+ c_text = TextMobject("Critical Point: $(1,0)$").scale(0.8).next_to(f_text).shift(DOWN+4*LEFT)
+ d_text = TextMobject("\\begin{equation*} D_2(1,0)= \\begin{vmatrix} 2 \\space & 0\\space \\\\ 0 & -4 \\end{vmatrix} \\end{equation*}",color = GREEN).scale(0.9)
+
+ t_text = TextMobject("$D_2 = -8<0$ (Saddle Point)", color = BLUE).scale(0.9).shift(2*DOWN)
+
+ self.play(ShowCreation(e_text))
+ self.wait(1)
+ self.play(ShowCreation(f_text))
+ self.wait(1)
+ self.play(ShowCreation(c_text))
+ self.wait(1)
+ self.play(ShowCreation(d_text))
+ self.wait(1)
+ self.play(ShowCreation(t_text))
+ self.wait(2)
+
+class SaddlePoint(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+ f = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ u**2-2*v**2-2*u
+ ]),v_min=-1,v_max=1,u_min=-1,u_max=1,checkerboard_colors=[RED_C,PURPLE_D,YELLOW_E],
+ resolution=(20, 20)).scale(1)
+
+ self.set_camera_orientation(phi=35 * DEGREES,theta=80*DEGREES)
+ self.begin_ambient_camera_rotation(rate=0.4)
+
+ f_text = TextMobject("$f(x,y) = x^2-2y^2-2x$",color = GREEN).shift(2*DOWN+2*RIGHT).scale(0.8)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.add(axes)
+ self.play(Write(f))
+ self.wait(3)
+
+
+class secondScene(Scene):
+ def construct(self):
+
+ h_text = TextMobject("NonDegenerate Hessian Matrix", color = GREEN).scale(1).shift(UP)
+ e_text = TextMobject("Case 1: Two positive eigenvalues", color = PINK).scale(1).shift(3*UP+2*LEFT)
+ f_text = TextMobject("$f(x,y) = 2x^2+3y^2-2yx$",color = TEAL).scale(0.8).next_to(e_text).shift(6*LEFT+DOWN)
+ c_text = TextMobject("Critical Point: $(0,0)$",color = TEAL).scale(0.8).next_to(f_text).shift(DOWN+4.5*LEFT)
+ d_text = TextMobject("\\begin{equation*} D_2(0,0)= \\begin{vmatrix} 4 \\space & -2\\space \\\\ -2 & 6 \\end{vmatrix} \\end{equation*}",color = PINK).scale(0.9)
+
+ t_text = TextMobject("$D_2 = 20>0$ (Relative Maxima or Relative Minima)", color = YELLOW).scale(0.9).shift(1*DOWN)
+ tm_text = TextMobject("$D_1 = \\frac{\\partial^2 f}{\\partial x^2} =4 >0$ (Relative Minima)", color = YELLOW).scale(0.9).shift(2*DOWN)
+
+
+ self.play(ShowCreation(h_text))
+ self.wait(1)
+ self.play(FadeOut(h_text))
+ self.wait(1)
+ self.play(ShowCreation(e_text))
+ self.wait(1)
+ self.play(ShowCreation(f_text))
+ self.wait(1)
+ self.play(ShowCreation(c_text))
+ self.wait(1)
+ self.play(ShowCreation(d_text))
+ self.wait(1)
+ self.play(ShowCreation(t_text))
+ self.wait(1)
+ self.play(ShowCreation(tm_text))
+ self.wait(2)
+ self.play(FadeOut(e_text),FadeOut(f_text),FadeOut(c_text),FadeOut(d_text),FadeOut(t_text),FadeOut(tm_text))
+
+class Minima(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+ f = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ 2*u**2+3*v**2-2*v*u
+ ]),v_min=-1,v_max=1,u_min=-1,u_max=1,checkerboard_colors=[BLUE_C,YELLOW_D,GREEN_E],
+ resolution=(20, 20)).scale(1)
+
+ self.set_camera_orientation(phi=10 * DEGREES,theta=90*DEGREES)
+ self.begin_ambient_camera_rotation(rate=0.2)
+
+ f_text = TextMobject("$f(x,y) = 2x^2+3y^2-2yx$",color = PURPLE).shift(2*DOWN+3*RIGHT).scale(0.8)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.add(axes)
+ self.play(Write(f))
+ self.wait(2)
+
+
+class thirdScene(Scene):
+ def construct(self):
+
+
+ e_text = TextMobject("Case 2: Two negative eigenvalues", color = RED).scale(1).shift(3*UP+2*LEFT)
+ f_text = TextMobject("$f(x,y) = -x^2-4y^2$",color = BLUE).scale(0.8).next_to(e_text).shift(6*LEFT+DOWN)
+ c_text = TextMobject("Critical Point: $(0,0)$",color = BLUE).scale(0.8).next_to(f_text).shift(DOWN+3.8*LEFT)
+ d_text = TextMobject("\\begin{equation*} D_2(0,0)= \\begin{vmatrix} -2 \\space & 0\\space \\\\ 0 & -8 \\end{vmatrix} \\end{equation*}",color = TEAL).scale(0.9)
+
+ t_text = TextMobject("$D_2 = 16>0$ (Relative Maxima or Relative Minima)" ).scale(0.9).shift(1*DOWN)
+ tm_text = TextMobject("$D_1 = \\frac{\\partial^2 f}{\\partial x^2} =-2 <0$ (Relative Maxima)").scale(0.9).shift(2*DOWN)
+
+
+ self.play(ShowCreation(e_text))
+ self.wait(1)
+ self.play(ShowCreation(f_text))
+ self.wait(1)
+ self.play(ShowCreation(c_text))
+ self.wait(1)
+ self.play(ShowCreation(d_text))
+ self.wait(1)
+ self.play(ShowCreation(t_text))
+ self.wait(1)
+ self.play(ShowCreation(tm_text))
+ self.wait(2)
+ self.play(FadeOut(e_text),FadeOut(f_text),FadeOut(c_text),FadeOut(d_text),FadeOut(t_text),FadeOut(tm_text))
+
+
+class Maxima(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+ f = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ -u**2-4*v**2
+ ]),v_min=-1,v_max=1,u_min=-1,u_max=1,checkerboard_colors=[BLUE_C,PURPLE_D,TEAL_E],
+ resolution=(20, 20)).scale(1)
+
+ self.set_camera_orientation(phi=75 * DEGREES)
+ self.begin_ambient_camera_rotation(rate=0.4)
+
+ f_text = TextMobject("$f(x,y) = -x^2-4y^2$",color = YELLOW).shift(2*DOWN+3*RIGHT).scale(0.8)
+ self.add_fixed_in_frame_mobjects(f_text)
+ self.add(axes)
+ self.play(Write(f))
+ self.wait(1)
+ self.move_camera(phi=30*DEGREES,theta=45*DEGREES,run_time=5)
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file4_Contour_Diagram.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file4_Contour_Diagram.gif
new file mode 100644
index 0000000..129fedc
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file4_Contour_Diagram.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file4_Contour_Diagram.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file4_Contour_Diagram.py
new file mode 100644
index 0000000..d3084e2
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/The-Second-Derivative-Test/file4_Contour_Diagram.py
@@ -0,0 +1,120 @@
+from manimlib.imports import*
+
+#---- contour diagram animation
+class ContourDiagram(ThreeDScene):
+ def construct(self):
+
+ heading = TextMobject("CONTOUR DIAGRAM", color = YELLOW).scale(1)
+
+ axes = ThreeDAxes()
+ label_x = TextMobject("$x$").shift([5.5,-0.5,0]) #---- x axis
+ label_y = TextMobject("$y$").shift([-0.5,5.5,0]).rotate(-4.5) #---- y axis
+
+ #---- surface of a paraboloid
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ np.cos(v)*u,
+ np.sin(v)*u,
+ u**2
+ ]),v_min = -2, v_max = 2, u_min = -2, u_max = 2, checkerboard_colors = [GREEN_B,GREEN_C,GREEN_D,GREEN_E]).shift([0,0,0]).scale(0.5)
+
+ #---- first contour projection
+ contour1 = ParametricSurface(
+ lambda u, v: np.array([
+ np.cos(TAU * v),
+ np.sin(TAU * v),
+ 2*(1 - 2.5*u)
+ ])).fade(0.5).scale(0.21).shift([0,0,1.01])
+
+ #---- first contour line
+ c_1 = Circle(color = BLUE).scale(0.21).shift([0,0,0]).rotate(0.1,DOWN)
+
+ #-------------------------------------------------
+
+ #---- second contour projection
+ contour2 = ParametricSurface(
+ lambda u, v: np.array([
+ np.cos(TAU * v),
+ np.sin(TAU * v),
+ 2*(1 - 1.6*u)
+ ])).fade(0.5).scale(0.41).shift([0,0,0.3]).set_color(RED)
+
+ #---- second contour line
+ c_2 = Circle(color = RED).scale(0.41).shift([0,0,0]).rotate(0.1,DOWN)
+
+ #-------------------------------------------------
+
+ #---- third contour projection
+ contour3 = ParametricSurface(
+ lambda u, v: np.array([
+ np.cos(TAU * v),
+ np.sin(TAU * v),
+ 2*(1 - 1.5*u)
+ ])).fade(0.5).scale(0.61).shift([0,0,0.4]).set_color(YELLOW)
+
+ #---- third contour line
+ c_3 = Circle(color = YELLOW).scale(0.61).shift([0,0,0])
+
+ #-------------------------------------------------
+
+ #---- fourth contour projection
+ contour4 = ParametricSurface(
+ lambda u, v: np.array([
+ np.cos(TAU * v),
+ np.sin(TAU * v),
+ 2*(1 - 1.5*u)
+ ])).fade(0.7).scale(0.81).shift([0,0,0.7]).set_color(PINK)
+
+ #---- fourth contour line
+ c_4 = Circle(color = PINK).scale(0.81).shift([0,0,0])
+
+ #-------------------------------------------------
+
+ #---- fifth contour projection
+ contour5 = ParametricSurface(
+ lambda u, v: np.array([
+ np.cos(TAU * v),
+ np.sin(TAU * v),
+ 2*(1 - 1.5*u)
+ ])).fade(0.7).scale(1.01).shift([0,0,1]).set_color(PURPLE)
+
+ #---- fifth contour line
+ c_5 = Circle(color = PURPLE).scale(1.01).shift([0,0,0])
+
+ c_text= TextMobject("Contour Lines").scale(0.5).shift(2*DOWN)
+ s = Square().scale(1.3)
+
+ self.set_camera_orientation(phi = 75 * DEGREES, theta = 10 * DEGREES)
+ self.add_fixed_in_frame_mobjects(heading)
+ self.wait(1)
+ self.play(FadeOut(heading))
+ self.wait(1)
+ self.add(axes)
+ self.add(label_x)
+ self.add(label_y)
+ self.play(Write(surface))
+ self.wait(1)
+ self.add(contour1)
+ self.wait(1)
+ self.play(Write(c_1))
+ self.play(ReplacementTransform(contour1,contour2))
+ self.wait(1)
+ self.play(Write(c_2))
+ self.play(ReplacementTransform(contour2,contour3))
+ self.wait(1)
+ self.play(Write(c_3))
+ self.play(ReplacementTransform(contour3,contour4))
+ self.wait(1)
+ self.play(Write(c_4))
+ self.play(ReplacementTransform(contour4,contour5))
+ self.wait(1)
+ self.play(Write(c_5))
+ self.wait(1)
+ self.play(FadeOut(contour5),FadeOut(axes),FadeOut(label_x),FadeOut(label_y),FadeOut(surface),FadeOut(contour5),FadeOut(contour4),FadeOut(contour3),FadeOut(contour2),FadeOut(contour1))
+ self.wait(1)
+ self.move_camera(phi=0 * DEGREES,theta= 90*DEGREES)
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(c_text)
+ self.wait(1)
+ self.play(ShowCreation(s),FadeOut(c_text))
+ self.wait(1)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file1_Visualization_of_dz.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file1_Visualization_of_dz.gif
new file mode 100644
index 0000000..e00a946
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file1_Visualization_of_dz.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file1_Visualization_of_dz.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file1_Visualization_of_dz.py
new file mode 100644
index 0000000..a097a96
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file1_Visualization_of_dz.py
@@ -0,0 +1,53 @@
+from manimlib.imports import*
+
+
+class firstScene(ThreeDScene):
+
+ def construct(self):
+
+ axes = ThreeDAxes().rotate(1.571)
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ u,
+ v,
+ u**2+v**2
+ ]),u_min=-1,u_max=1, v_min=-1,v_max=1).set_color("#FF69B4").fade(0.6).scale(2).shift(3*UP+1*LEFT)
+
+ d = Dot([1.4,1.75,1],color = '#00FFFF').rotate(1.571,UP)
+ d2 = Dot([2,2,1],color = '#00FFFF').rotate(1.571,UP)
+
+ p1 = TextMobject("$P_1$",color ='#ADFF2F').scale(0.6).shift(2*RIGHT+1*UP)
+ p2 = TextMobject("$P_2$",color = '#ADFF2F').scale(0.6).shift(2.6*RIGHT+0.9*UP)
+
+ l = DashedLine(color = '#800000').rotate(1.571,UP).scale(1).shift(1.7*UP+1.6*RIGHT)
+ l2 = DashedLine(color = '#800000').rotate(1.571,UP).scale(0.8).shift(2.26*UP+1.2*RIGHT)
+
+ l_text = TextMobject("$(x_1,y_1)$",color = '#ADFF2F').scale(0.6).shift(2*RIGHT+1.6*DOWN)
+ l2_text = TextMobject("$(x_2,y_2)$",color = '#ADFF2F').scale(0.6).shift(2.7*RIGHT+1.2*DOWN)
+
+ a = Arrow(color = '#FFFACD').scale(0.7).rotate(1.38,RIGHT).shift(2.5*LEFT+3.1*UP)
+
+ a_text = TextMobject("$dz$",color='#800000').scale(0.5).shift(2.3*RIGHT+0.5*UP)
+
+ plane = Rectangle(color = '#E6E6FA',fill_opacity = 1).scale(3).shift(1*RIGHT+3*UP).fade(0.9)
+
+ label = TextMobject("$z = f(x,y)$").scale(0.6).shift(3.5*RIGHT+1.8*UP)
+
+ self.add(axes)
+ self.set_camera_orientation(phi=75*DEGREES,theta=-10*DEGREES)
+ self.wait(1)
+ self.play(Write(plane))
+ self.play(Write(surface))
+ self.add_fixed_in_frame_mobjects(label)
+ self.wait(1)
+ self.play(ShowCreation(l),ShowCreation(l2),Write(d),Write(d2))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(p1)
+ self.add_fixed_in_frame_mobjects(p2)
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(l_text)
+ self.add_fixed_in_frame_mobjects(l2_text)
+ self.play(ShowCreation(a))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(a_text)
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file2_Differentials.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file2_Differentials.gif
new file mode 100644
index 0000000..620b49e
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file2_Differentials.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file2_Differentials.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file2_Differentials.py
new file mode 100644
index 0000000..b40be70
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file2_Differentials.py
@@ -0,0 +1,72 @@
+from manimlib.imports import*
+
+
+class firstScene(ThreeDScene):
+
+ def construct(self):
+
+ axes = ThreeDAxes()
+
+ s = Rectangle(color = '#00FF7F',fill_opacity=0.3).shift(2.3*UP+3.9*LEFT).scale(1).rotate(0.2,UP) #----surface z = f(x,y)
+
+ label_y = TextMobject("$y$").shift(5*RIGHT+0.4*DOWN).rotate(1.571)
+ label_x = TextMobject("$x$").shift(-0.1*UP+5.6*RIGHT).scale(0.5)
+
+ plane = Rectangle(color = '#E6E6FA',fill_opacity = 1).scale(3).shift(-1*RIGHT+3*UP).fade(0.9)
+
+ d = Dot([1,2,1],color = '#9400D3').rotate(1.571,UP)
+ d2 = Dot([2,2.9,1],color = '#9400D3').rotate(1.571,UP)
+
+ p1 = TextMobject("$P_1$",color ='#ADFF2F').scale(0.6).shift(2*RIGHT+1*UP)
+ p2 = TextMobject("$P_2$",color = '#ADFF2F').scale(0.6).shift(2.6*RIGHT+0.4*UP)
+
+
+ l1 = DashedLine(color = '#00BFFF').scale(1.6).shift(3.5*UP+3.25*LEFT).rotate(1.571)
+ l2 = DashedLine(color = '#00BFFF').scale(1).shift(4*UP+2*LEFT).rotate(1.571)
+
+ label_dz= TextMobject("$dz$").scale(0.4).shift(5.3*RIGHT+0.4*UP)
+
+
+ l3 = Line(color = '#FFDAB9').scale(0.8).shift(1.95*UP+0.7*RIGHT).rotate(1.571,DOWN).fade(0.7)
+ l4 = Line(color = '#FFDAB9').scale(0.6).shift(2.86*UP+0.9*RIGHT).rotate(1.571,DOWN).fade(0.7)
+
+ line_y1 = DashedLine(color = '#00BFFF').scale(1.3).shift(0.82*UP+3.25*RIGHT).rotate(1.571)
+ line_y2 = DashedLine(color = '#00BFFF').scale(1.7).shift(1.2*UP+2.8*RIGHT).rotate(1.571)
+
+ label_dy= TextMobject("$dy$").scale(0.6).shift(3*RIGHT+0.8*DOWN).rotate(math.radians(90))
+
+ line_x1 = DashedLine(color = '#00BFFF').scale(1.5).shift(2.2*UP+1.6*RIGHT).rotate(1.571,RIGHT)
+ line_x2 = DashedLine(color = '#00BFFF').scale(1.2).shift(2.9*UP+1.6*RIGHT).rotate(1.571,RIGHT)
+
+ label_dx= TextMobject("$dx$").scale(0.4).shift(-0.4*UP+2.5*RIGHT)
+
+ label = TextMobject("$f(x,y)$").scale(0.6).shift(4*RIGHT+3*UP)
+
+
+ self.add(axes)
+ self.set_camera_orientation(phi=75*DEGREES,theta=10*DEGREES)
+ self.play(Write(plane))
+ self.play(ShowCreation(label_y))
+ self.add_fixed_in_frame_mobjects(label_x)
+ self.play(Write(s))
+ self.add_fixed_in_frame_mobjects(label)
+ self.wait(1)
+ self.play(Write(d),Write(d2))
+ self.add_fixed_in_frame_mobjects(p1)
+ self.add_fixed_in_frame_mobjects(p2)
+ self.wait(1)
+ self.play(Write(l1))
+ self.play(Write(l2))
+ self.add_fixed_in_frame_mobjects(label_dz)
+ self.wait(1)
+ self.play(Write(l3))
+ self.play(Write(l4))
+ self.wait(1)
+ self.play(Write(line_y1))
+ self.play(Write(line_y2))
+ self.play(ShowCreation(label_dy))
+ self.wait(1)
+ self.play(Write(line_x1))
+ self.play(Write(line_x2))
+ self.add_fixed_in_frame_mobjects(label_dx)
+ self.wait(1)
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file3_Total_differential_of_z.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file3_Total_differential_of_z.gif
new file mode 100644
index 0000000..5aae2a1
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file3_Total_differential_of_z.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file3_Total_differential_of_z.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file3_Total_differential_of_z.py
new file mode 100644
index 0000000..b29a7a3
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file3_Total_differential_of_z.py
@@ -0,0 +1,91 @@
+from manimlib.imports import*
+
+class firstScene(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes().fade(0.5)
+ plane = Rectangle(color = '#E6E6FA',fill_opacity = 1).scale(3).shift(-1*RIGHT+3*UP).fade(0.9)
+ label_x = TextMobject("$x$").shift(5*RIGHT+0.4*DOWN).rotate(1.571)
+ label_y = TextMobject("$y$").shift(0.3*DOWN+5.6*RIGHT).scale(0.5)
+ label_z = TextMobject("$z$").shift(3.5*UP+0.2*LEFT).scale(0.5)
+
+ s1 = Square(color = '#00FF00',fill_opacity=0.4).shift([1,1,0])
+ s2 = Square(color = '#00FF00',fill_opacity=0.4).shift([1,1,3]).scale(0.95)
+
+ l1 = Line([2,0,3],[2,0,0],color = '#FFFACD')
+ l2 = Line([0,2,3],[0,2,0],color = '#FFFACD')
+ l3 = Line([2,1.95,3],[2,2,0],color = '#FFFACD')
+
+ d1 = Dot([2,0,1.5],color = '#FFD700').rotate(1.571,UP)
+ d1_text = TextMobject("$P1$").scale(0.4).shift(1.2*LEFT+1.1*UP)
+
+ d2 = Dot([0,2,3],color = '#FFD700').rotate(1.571,UP)
+ d2_text = TextMobject("$P2$").scale(0.4).shift(2.3*RIGHT+3.1*UP)
+
+ d3 = Dot([2,2,2],color = '#FFD700').rotate(1.571,UP)
+ d3_text = TextMobject("$Q$").scale(0.4).shift([1.6,-1,0]+2.5*UP)
+
+ s3 = Square().shift([1,1,1.5]).scale(0.95)
+ s4 = Square().shift([1,1,2]).scale(0.95)
+
+ m1_line = DashedLine([2,0,1.5],[2,2,2],color = '#87CEEB')
+ m2_line = DashedLine([2,2,2],[0,2,3],color = '#87CEEB')
+
+ dx_line = Line([2,2,0],[4,2,0],color = '#00FF7F')
+ dy_line = Line([2,2,0],[2,4,0],color = '#00FF7F')
+
+ dx = DashedLine([3.5,0,0],[3.5,2,0],color = '#87CEEB')
+ dy = DashedLine([0,3.5,0],[2,3.5,0],color = '#87CEEB')
+
+ dx_text = TextMobject("$dx$").scale(0.8).shift([4,1,0]).rotate(1.571)
+ dy_text = TextMobject("$dy$").scale(0.8).shift([1,3.8,0]).rotate(math.radians(180))
+
+ parx_line = Line([0,2,1.5],[0,5,1.5],color = '#00FF7F')
+ parm_line = Line([0,2,2],[0,5,2],color = '#00FF7F')
+ pary_line = Line([0,2.1,3],[0,5,3],color = '#00FF7F')
+
+ delx = DashedLine([0,4,2],[0,4,1.5],color = '#F0F8FF')
+ dely = DashedLine([0,4,3],[0,4,2],color = '#FAEBD7')
+
+ dely_text = TextMobject("$\\frac{\\partial z}{\\partial y}dy$").shift(4.6*RIGHT+2.3*UP).scale(0.4)
+ delx_text = TextMobject("$\\frac{\\partial z}{\\partial x}dx$").shift(4.6*RIGHT+1.4*UP).scale(0.4)
+
+
+ self.set_camera_orientation(phi=75*DEGREES,theta=20*DEGREES)
+ self.add(axes)
+ self.play(Write(plane))
+ self.play(ShowCreation(label_x))
+ self.add_fixed_in_frame_mobjects(label_y)
+ self.add_fixed_in_frame_mobjects(label_z)
+ self.wait(1)
+ self.play(Write(s2))
+ self.wait(1)
+ self.play(Write(l1),Write(l2),Write(l3))
+ self.wait(1)
+ self.play(Write(s1))
+ self.wait(1)
+ self.play(ShowCreation(d1))
+ self.add_fixed_in_frame_mobjects(d1_text)
+ self.play(ShowCreation(d2))
+ self.add_fixed_in_frame_mobjects(d2_text)
+ self.wait(1)
+ self.play(ShowCreation(d3))
+ self.add_fixed_in_frame_mobjects(d3_text)
+ self.play(ShowCreation(m1_line))
+ self.play(ShowCreation(m2_line))
+ self.wait(1)
+ self.play(ShowCreation(dx_line),ShowCreation(dx),ShowCreation(dx_text))
+ self.wait(1)
+ self.play(ShowCreation(dy_line),ShowCreation(dy),ShowCreation(dy_text))
+ self.wait(2)
+ self.play(Write(s3))
+ self.play(Write(s4))
+ self.wait(1)
+ self.play(ShowCreation(parx_line),ShowCreation(parm_line),ShowCreation(pary_line))
+ self.wait(1)
+ self.play(ShowCreation(dely))
+ self.add_fixed_in_frame_mobjects(dely_text)
+ self.wait(1)
+ self.play(ShowCreation(delx))
+ self.add_fixed_in_frame_mobjects(delx_text)
+ self.wait(1)
+
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file4_total_differential_change.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file4_total_differential_change.gif
new file mode 100644
index 0000000..f2227a8
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file4_total_differential_change.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file4_total_differential_change.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file4_total_differential_change.py
new file mode 100644
index 0000000..78e41a2
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file4_total_differential_change.py
@@ -0,0 +1,54 @@
+from manimlib.imports import*
+
+
+class firstScene(ThreeDScene):
+
+ def construct(self):
+
+ axes = ThreeDAxes()
+
+ s = Rectangle(color = '#F08080',fill_opacity=1).fade(0.7).shift(1.9*UP+5*LEFT).scale(0.9)#----surface z = f(x,y)
+
+ s2= Rectangle(color = '#F08080',fill_opacity=1).fade(0.7).shift(2.4*UP+3.1*RIGHT).scale(0.6) #----reflection of the surface on the x-y plane
+
+ l1 = DashedLine(color = '#AFEEEE').rotate(1.571,UP).scale(1).shift(1.53*UP+1.5*RIGHT)
+ l2 = DashedLine(color = '#AFEEEE').rotate(1.571,UP).scale(1).shift(2.9*UP+1.4*RIGHT)
+ l3 = DashedLine(color = '#AFEEEE').rotate(1.571,UP).scale(1).shift(1.5*UP-1.6*RIGHT)
+ l4 = DashedLine(color = '#AFEEEE').rotate(1.571,UP).scale(1).shift(2.9*UP-1.75*RIGHT)
+
+
+ l1_text = TextMobject("$(x+\\triangle x,y)$").shift(RIGHT+1.7*DOWN).scale(0.4)
+ l2_text = TextMobject("$(x+\\triangle x,y+\\triangle y)$").shift(3*RIGHT+1.8*DOWN).scale(0.4)
+ l3_text = TextMobject("$f(x,y)$").shift(1.6*RIGHT+1.5*UP).scale(0.4)
+ l4_text = TextMobject("$(x,y+\\triangle y)$").shift(3.5*RIGHT+0.7*DOWN).scale(0.4)
+
+ label_x = TextMobject("$x$").shift(5*RIGHT+0.4*DOWN)
+ label_y = TextMobject("$y$").shift(5*UP-0.6*RIGHT)
+
+ self.add(axes)
+ self.set_camera_orientation(phi=75*DEGREES,theta=10*DEGREES)
+ self.wait(1)
+ self.play(ShowCreation(label_x),ShowCreation(label_y))
+ self.play(Write(s))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(l3_text)
+ self.wait(1)
+ self.play(Write(l3))
+ self.wait(1)
+ self.play(Write(l1))
+ self.add_fixed_in_frame_mobjects(l1_text)
+ self.wait(1)
+ self.play(Write(l2))
+ self.add_fixed_in_frame_mobjects(l2_text)
+ self.wait(1)
+ self.play(Write(l4))
+ self.add_fixed_in_frame_mobjects(l4_text)
+ self.wait(1)
+ self.play(Write(s2))
+ self.wait(1)
+
+
+
+
+
+
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file5_Total_differential_approximation.gif b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file5_Total_differential_approximation.gif
new file mode 100644
index 0000000..4f4627d
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file5_Total_differential_approximation.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file5_Total_differential_approximation.py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file5_Total_differential_approximation.py
new file mode 100644
index 0000000..83017ed
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Total-Differential/file5_Total_differential_approximation.py
@@ -0,0 +1,48 @@
+from manimlib.imports import*
+
+
+class firstScene(ThreeDScene):
+
+ def construct(self):
+
+ axes = ThreeDAxes().rotate(1.571)
+ surface = ParametricSurface(
+ lambda u, v: np.array([
+ np.sin(u),
+ v,
+ -u**2-v
+ ]),u_min=-1,u_max=1, v_min=-1,v_max=1).set_color("#00008B").scale(2).shift(3.8*UP+2*LEFT)
+
+ d = Dot([1.4,1.75,1],color = '#00FFFF').rotate(1.571,UP)
+ d2 = Dot([2,2,1],color = '#00FFFF').rotate(1.571,UP)
+
+ l = DashedLine(color = '#800000').rotate(1.571,UP).scale(1).shift(1.7*UP+1.6*RIGHT)
+ l2 = DashedLine(color = '#800000').rotate(1.571,UP).scale(0.8).shift(2.26*UP+1.2*RIGHT)
+
+ l_text = TextMobject("$(x_1,y_1)$",color = '#ADFF2F').scale(0.6).shift(2*RIGHT+1.6*DOWN)
+ l2_text = TextMobject("$(x_2,y_2)$",color = '#ADFF2F').scale(0.6).shift(2.7*RIGHT+1.2*DOWN)
+
+ plane = Rectangle(color = '#E6E6FA',fill_opacity = 1).scale(3).shift(1*RIGHT+3*UP).fade(0.9)
+
+ tangentplane = Rectangle(color = '#E6E6FA',fill_opacity = 1).scale(1.1).shift(2*LEFT+3.4*UP).fade(0.5).rotate(0.8,RIGHT)
+ tangentplane_text = TextMobject("Tangent Plane").scale(0.4).shift(3*RIGHT+1*UP)
+
+ label = TextMobject("$z = f(x,y)$").scale(0.6).shift(4*RIGHT+3*UP)
+
+
+ self.add(axes)
+ self.set_camera_orientation(phi=75*DEGREES,theta=-10*DEGREES)
+ self.wait(1)
+ self.play(Write(plane))
+ self.wait(1)
+ self.play(Write(surface))
+ self.add_fixed_in_frame_mobjects(label)
+ self.wait(1.5)
+ self.play(ShowCreation(l),ShowCreation(l2),Write(d),Write(d2))
+ self.wait(1)
+ self.add_fixed_in_frame_mobjects(l_text)
+ self.add_fixed_in_frame_mobjects(l2_text)
+ self.wait(1)
+ self.play(Write(tangentplane))
+ self.add_fixed_in_frame_mobjects(tangentplane_text)
+ self.wait(2)
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/README.md b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/README.md
index b50200d..7ff6b61 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/README.md
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/README.md
@@ -4,6 +4,6 @@ Github Account : <a href="https://github.com/nishanpoojary">nishanpoojary</a>
## Sub-Topics Covered:
+ Scalar Functions
+ Multivariable Functions
-+ Limits and continuity of Multivariable Function
++ Limits and Continuity of Multivariable Functions
+ Partial Derivatives
+ Directonal Derivatives
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_level_curves.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_level_curves.gif
deleted file mode 100644
index 2df2fde..0000000
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_level_curves.gif
+++ /dev/null
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_level_curves2.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_level_curves2.gif
deleted file mode 100644
index 724c27d..0000000
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_level_curves2.gif
+++ /dev/null
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/Limits_and_Continuity_of_Multivariable_Function_Quiz.pdf b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/Limits_and_Continuity_of_Multivariable_Function_Quiz.pdf
new file mode 100644
index 0000000..99918e5
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/Limits_and_Continuity_of_Multivariable_Function_Quiz.pdf
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file1_epsilon_delta_defn.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file1_epsilon_delta_defn.py
new file mode 100644
index 0000000..63b6165
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file1_epsilon_delta_defn.py
@@ -0,0 +1,120 @@
+from manimlib.imports import *
+
+class EpsilonDelta(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes() # creates a 3D Axis
+
+
+ sphere = ParametricSurface(
+ lambda u, v: np.array([
+ 2*np.sin(u)*np.cos(v),
+ 2*np.sin(u)*np.sin(v),
+ 2*np.cos(u)
+ ]),u_min=0,u_max=PI/4,v_min=0,v_max=PI/2,checkerboard_colors=[RED_D, RED_E],
+ resolution=(15, 32)).scale(2)
+ #sphere.shift(0.5*RIGHT+0.5*UP)
+
+ #self.set_camera_orientation(phi=0*DEGREES,theta=270*DEGREES)
+ self.set_camera_orientation(phi=75 * DEGREES)
+
+
+
+ circle = Circle(radius= 0.4,color = GREEN)
+ circle.shift(0.5*RIGHT+0.5*UP)
+
+ line1 = DashedLine(np.array([0.5, 0.1,0]), np.array([0.5, 0.1,2.1]), color = BLUE_E)
+ line2 = DashedLine(np.array([0.5, 0.9,0]), np.array([0.5, 0.9,1.7]), color = BLUE_E)
+ line3 = DashedLine(np.array([0, 0,2.1]), np.array([0.5, 0.1,2.1]), color = YELLOW_C)
+ line4 = DashedLine(np.array([0, 0,1.7]), np.array([0.5, 0.9,1.7]), color = YELLOW_C)
+
+ dot1 = Sphere()
+ dot1.scale(0.01)
+ dot1.move_to(np.array([0,0,1.9]))
+ dot1.set_fill(BLUE_E)
+
+ temp_func1 = TextMobject(r"$L$")
+ temp_func1.scale(0.6)
+ temp_func1.set_color(BLUE_E)
+
+ dot2 = Sphere()
+ dot2.scale(0.01)
+ dot2.move_to(np.array([0,0,1.7]))
+ dot2.set_fill(PURPLE)
+
+ temp_func2 = TextMobject(r"$L - \epsilon$")
+ temp_func2.scale(0.6)
+ temp_func2.set_color(PURPLE)
+
+ dot3 = Sphere()
+ dot3.scale(0.01)
+ dot3.move_to(np.array([0,0,2.1]))
+ dot3.set_fill(PURPLE)
+
+ temp_func3 = TextMobject(r"$L + \epsilon$")
+ temp_func3.scale(0.6)
+ temp_func3.set_color(PURPLE)
+
+ self.add(axes)
+
+ self.play(ShowCreation(dot1))
+ self.add_fixed_in_frame_mobjects(temp_func1)
+ temp_func1.move_to(1.9*UP)
+ self.play(Write(temp_func1))
+
+ self.play(ShowCreation(dot2))
+ self.add_fixed_in_frame_mobjects(temp_func2)
+ temp_func2.move_to(1.7*UP)
+ self.play(Write(temp_func2))
+
+ self.play(ShowCreation(dot3))
+ self.add_fixed_in_frame_mobjects(temp_func3)
+ temp_func3.move_to(2.1*UP)
+ self.play(Write(temp_func3))
+
+
+ circle_center = Sphere()
+ circle_center.scale(0.05)
+ circle_center.move_to(np.array([0.5,0.5,0]))
+ circle_center.set_fill(GREEN)
+
+ temp_circle_center = TextMobject(r"$(a,b,0)$")
+ temp_circle_center.scale(0.5)
+ temp_circle_center.set_color(GREEN)
+
+ curve_circle_center = Sphere()
+ curve_circle_center.scale(0.05)
+ curve_circle_center.move_to(np.array([0.5,0.5,1.9]))
+ curve_circle_center.set_fill(BLUE_E)
+
+ temp_curve_circle_center = TextMobject(r"$(a,b,L)$")
+ temp_curve_circle_center.scale(0.5)
+ temp_curve_circle_center.set_color(BLUE)
+
+ delta_lab = TextMobject(r"$\delta - disk$")
+ delta_lab.scale(0.5)
+ delta_lab.set_color(PINK)
+
+ self.play(ShowCreation(circle_center))
+ self.add_fixed_in_frame_mobjects(temp_circle_center)
+ temp_circle_center.move_to(1.5*RIGHT)
+ self.play(Write(temp_circle_center))
+
+ self.play(ShowCreation(curve_circle_center))
+ self.add_fixed_in_frame_mobjects(temp_curve_circle_center)
+ temp_curve_circle_center.move_to(1.9*UP+1*RIGHT)
+ self.play(Write(temp_curve_circle_center))
+
+
+ self.add_fixed_in_frame_mobjects(delta_lab)
+ delta_lab.move_to(0.4*DOWN+1.7*RIGHT)
+ self.play(Write(delta_lab))
+
+
+
+
+
+ self.begin_ambient_camera_rotation(rate=0.2)
+ self.play(Write(sphere))
+ self.play(ShowCreation(circle), ShowCreation(line1), ShowCreation(line2))
+ self.play(ShowCreation(line3), ShowCreation(line4))
+ self.wait(8)
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Limits and Continuity of Multivariable Functions/limit_approach_point.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file2_limit_approach_point.py
index 57d1d45..57d1d45 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Limits and Continuity of Multivariable Functions/limit_approach_point.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file2_limit_approach_point.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file3_limit_func.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file3_limit_func.py
new file mode 100644
index 0000000..02e00e8
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file3_limit_func.py
@@ -0,0 +1,30 @@
+from manimlib.imports import *
+
+class LimitFunc(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+
+ text3d = TextMobject(r"$f(x,y) = \frac{x^2 - y^2}{x^2 + y^2}$")
+ self.add_fixed_in_frame_mobjects(text3d)
+
+ text3d.to_corner(UL)
+
+ text3d.set_color_by_gradient(RED, ORANGE, YELLOW, GREEN, BLUE, PURPLE)
+
+ self.play(Write(text3d))
+ self.wait(1)
+
+ limit_func = ParametricSurface(
+ lambda u, v: np.array([
+ u*np.cos(v),
+ u*np.sin(v),
+ (np.cos(v)*np.cos(v) - np.sin(v)*np.sin(v))/3
+ ]),u_min=-3,u_max=3,v_min=0,v_max=2*PI,checkerboard_colors=[YELLOW_C, YELLOW_E],
+ resolution=(15, 32)).scale(2)
+
+ self.set_camera_orientation(phi=80 * DEGREES)
+ self.begin_ambient_camera_rotation(rate=0.3)
+
+ self.add(axes)
+ self.play(Write(limit_func))
+ self.wait(10) \ No newline at end of file
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file4_continuity_func.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file4_continuity_func.py
new file mode 100644
index 0000000..551c8a8
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/file4_continuity_func.py
@@ -0,0 +1,32 @@
+from manimlib.imports import *
+
+class ContinuityFunc(ThreeDScene):
+ def construct(self):
+ axes = ThreeDAxes()
+
+ text3d = TextMobject(r"$f(x,y) = \frac{3x^2y}{x^2 + y^2}$")
+ self.add_fixed_in_frame_mobjects(text3d)
+
+ text3d.to_corner(UL)
+
+ text3d.set_color_by_gradient(RED, ORANGE, YELLOW, GREEN, BLUE, PURPLE)
+
+ self.play(Write(text3d))
+ self.wait(1)
+
+ continuity_func = ParametricSurface(
+ lambda u, v: np.array([
+ u*np.cos(v),
+ u*np.sin(v),
+ 3*u*np.cos(v)*np.cos(v)*np.sin(v)
+ ]),u_min=-1.5,u_max=1.5,v_min=0,v_max=2*PI,checkerboard_colors=[YELLOW_C, YELLOW_E],
+ resolution=(15, 32)).scale(2)
+
+
+
+ self.set_camera_orientation(phi=80 * DEGREES)
+ self.begin_ambient_camera_rotation(rate=0.3)
+
+ self.add(axes)
+ self.play(Write(continuity_func))
+ self.wait(8) \ No newline at end of file
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file1_epsilon_delta_defn.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file1_epsilon_delta_defn.gif
new file mode 100644
index 0000000..68f637e
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file1_epsilon_delta_defn.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Limits and Continuity of Multivariable Functions/gifs/limit_approach_point.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file2_limit_approach_point.gif
index 830b6f1..830b6f1 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Limits and Continuity of Multivariable Functions/gifs/limit_approach_point.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file2_limit_approach_point.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file3_limit_func.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file3_limit_func.gif
new file mode 100644
index 0000000..07b23be
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file3_limit_func.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file4_continuity_func.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file4_continuity_func.gif
new file mode 100644
index 0000000..560e0f1
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/limits-and-continuity-of-multivariable-functions/gifs/file4_continuity_func.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/Multivariable_Functions_Quiz.pdf b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/Multivariable_Functions_Quiz.pdf
index 7895843..7895843 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/Multivariable_Functions_Quiz.pdf
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/Multivariable_Functions_Quiz.pdf
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_respresntation.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file1_multivariable_func_respresentation.py
index 4bfcf21..4bfcf21 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_respresntation.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file1_multivariable_func_respresentation.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_examples.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file2_multivariable_func_examples.py
index 7322e47..7322e47 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_examples.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file2_multivariable_func_examples.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_plot_sphere.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file3_plot_sphere.py
index baf08b1..baf08b1 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_plot_sphere.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file3_plot_sphere.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_vectorvf_sine.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file4_vectorvf_sine.py
index 06e225e..06e225e 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_vectorvf_sine.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file4_vectorvf_sine.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_derivative_vectorvf.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file5_derivative_vectorvf.py
index 466e389..466e389 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/multivariable_func_derivative_vectorvf.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/file5_derivative_vectorvf.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_respresntation.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file1_multivariable_func_respresentation.gif
index a173bda..a173bda 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_respresntation.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file1_multivariable_func_respresentation.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_examples.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file2_multivariable_func_examples.gif
index 11f66f1..11f66f1 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_examples.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file2_multivariable_func_examples.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_plot_sphere.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file3_plot_sphere.gif
index ad7582c..ad7582c 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_plot_sphere.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file3_plot_sphere.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_vectorvf_sine.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file4_vectorvf_sine.gif
index 4f6b931..4f6b931 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_vectorvf_sine.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file4_vectorvf_sine.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_derivative_vectorvf.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file5_derivative_vectorvf.gif
index a94de90..a94de90 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Multivariable Functions/gifs/multivariable_func_derivative_vectorvf.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/multivariable-functions/gifs/file5_derivative_vectorvf.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/Scalar_Function_Quiz.pdf b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/Scalar_Function_Quiz.pdf
index 6d94a2c..6d94a2c 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/Scalar_Function_Quiz.pdf
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/Scalar_Function_Quiz.pdf
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_domain_range.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file1_domain_range.py
index 9b1ca7b..9b1ca7b 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_domain_range.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file1_domain_range.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_application.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file2_scalar_function_application.py
index 56b3e53..56b3e53 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_application.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file2_scalar_function_application.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_parabola_example.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file3_parabola_example.py
index 74dc063..74dc063 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_parabola_example.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file3_parabola_example.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_neural_nets.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file4_neural_nets.py
index eb6bf45..eb6bf45 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/scalar_function_neural_nets.py
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file4_neural_nets.py
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/domain_range.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/gifs/file1_domain_range.gif
index d0351e5..d0351e5 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/domain_range.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/gifs/file1_domain_range.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_application.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/gifs/file2_scalar_function_application.gif
index 831ec8e..831ec8e 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_application.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/gifs/file2_scalar_function_application.gif
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diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_parabola_example.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/gifs/file3_parabola_example.gif
index 3fdecf4..3fdecf4 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_parabola_example.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/gifs/file3_parabola_example.gif
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diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_neural_nets.gif b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/gifs/file4_neural_nets.gif
index 9d24688..9d24688 100644
--- a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/Scalar Functions/gifs/scalar_function_neural_nets.gif
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/gifs/file4_neural_nets.gif
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diff --git a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/README.md b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/README.md
index e69de29..0af7aa1 100644
--- a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/README.md
+++ b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/README.md
@@ -0,0 +1,8 @@
+**file1_flux_through_sphere.py**
+![file1_flux_through_sphere](file1_flux_through_sphere.gif)
+**file2_mobius_strip.py**
+![file2_mobius_strip](file2_mobius_strip.gif)
+**file3_normal_vector.py**
+![file3_normal_vector](file3_normal_vector.gif)
+**file4_cube_surface.py**
+![file4_cube_surface](file4_cube_surface.gif)
diff --git a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/file4_cube_surface.py b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/file4_cube_surface.py
index 5963996..9301a00 100644
--- a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/file4_cube_surface.py
+++ b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/flux/file4_cube_surface.py
@@ -43,29 +43,186 @@ class cuber(ThreeDScene):
n1.rotate(PI/2,axis=RIGHT)
n1.shift(3*RIGHT+1.3*OUT+DOWN)
+ spaceloc = [[0,0,2],[1,0,2],[-1,0,2],[2,0,2],[-2,0,2],[3,0,2],[-3,0,2],
+ [0,1,2],[1,1,2],[-1,1,2],[2,1,2],[-2,1,2],[3,1,2],[-3,1,2],
+ [0,-1,2],[1,-1,2],[-1,-1,2],[2,-1,2],[-2,-1,2],[3,-1,2],[-3,-1,2],
+ [0,2,2],[1,2,2],[-1,2,2],[2,2,2],[-2,2,2],[3,2,2],[-3,2,2],
+ [0,-2,2],[1,-2,2],[-1,-2,2],[2,-2,2],[-2,-2,2],[3,-2,2],[-3,-2,2],
+ [0,3,2],[1,3,2],[-1,3,2],[2,3,2],[-2,3,2],[3,3,2],[-3,3,2],
+ [0,3,2],[1,3,2],[-1,3,2],[2,3,2],[-2,3,2],[3,3,2],[-3,3,2],
+ [0,4,2],[1,4,2],[-1,4,2],[2,4,2],[-2,4,2],[3,4,2],[-3,4,2],
+ [0,4,2],[1,4,2],[-1,4,2],[2,4,2],[-2,4,2],[3,4,2],[-3,4,2],
+ [0,5,2],[1,5,2],[-1,5,2],[2,5,2],[-2,5,2],[3,5,2],[-3,5,2],
+ [0,5,2],[1,5,2],[-1,5,2],[2,5,2],[-2,5,2],[3,5,2],[-3,5,2],
+ [0,6,2],[1,6,2],[-1,6,2],[2,6,2],[-2,6,2],[3,6,2],[-3,6,2],
+ [0,1.5,2],[1,1.5,2],[-1,1.5,2],[2,1.5,2],[-2,1.5,2],[3,1.5,2],[-3,1.5,2],
+ [0,3,2],[1,3,2],[-1,3,2],[2,3,2],[-2,3,2],[3,3,2],[-3,3,2]]
+
+
+ veclist1=[Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E)]
+
+
+
+
+
+ [veclist1[i].rotate(PI/4,axis=RIGHT) for i in range(10,30,1)]
+ [veclist1[i].rotate(PI/4,axis=RIGHT) for i in range(40,80,2)]
+ [veclist1[i].rotate(PI/6,axis=OUT) for i in range(98)]
+ [veclist1[i].rotate(PI/8,axis=DOWN) for i in range(98)]
+ vectorfield1=VGroup(*veclist1)
+ [veclist1[i].shift(spaceloc[i]) for i in range(98)]
- self.set_camera_orientation(phi=75 * DEGREES,theta=-15*DEGREES)
+
+
+ veclist2=[Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),
+ Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E),Vector(color=GOLD_E)]
+
+
+
+
+
+ [veclist2[i].rotate(PI/4,axis=RIGHT) for i in range(10,30,1)]
+ [veclist2[i].rotate(PI/4,axis=RIGHT) for i in range(40,80,2)]
+ [veclist2[i].rotate(PI/6,axis=OUT) for i in range(98)]
+ [veclist2[i].rotate(PI/8,axis=DOWN) for i in range(98)]
+ vectorfield2=VGroup(*veclist2)
+ [veclist2[i].shift(spaceloc[i]) for i in range(98)]
+
+
+
+ veclist3=[Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector()]
+
+
+
+
+
+ [veclist3[i].rotate(PI/4,axis=RIGHT) for i in range(10,30,1)]
+ [veclist3[i].rotate(PI/4,axis=RIGHT) for i in range(40,80,2)]
+ [veclist3[i].rotate(PI/6,axis=OUT) for i in range(98)]
+ [veclist3[i].rotate(PI/8,axis=DOWN) for i in range(98)]
+ vectorfield3=VGroup(*veclist3)
+ [veclist3[i].shift(spaceloc[i]) for i in range(98)]
+
+
+
+
+ veclist4=[Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector(),
+ Vector(color=RED),Vector(color=GREEN),Vector(color=BLUE),Vector(color=PINK),Vector(color=MAROON),Vector(color=GREEN),Vector()]
+
+
+
+
+
+ [veclist4[i].rotate(PI/4,axis=RIGHT) for i in range(10,30,1)]
+ [veclist4[i].rotate(PI/4,axis=RIGHT) for i in range(40,80,2)]
+ [veclist4[i].rotate(PI/6,axis=OUT) for i in range(98)]
+ [veclist4[i].rotate(PI/8,axis=DOWN) for i in range(98)]
+ vectorfield4=VGroup(*veclist4)
+ [veclist4[i].shift(spaceloc[i]) for i in range(98)]
+
+
+ vectorfield1.shift(1.5*DOWN)
+ vectorfield2.shift(IN+1.5*DOWN)
+ vectorfield3.shift(2*IN+1.5*DOWN)
+ vectorfield4.shift(3*IN+1.5*DOWN)
+
+ vectors=[vectorfield1,vectorfield2,vectorfield3,vectorfield4]
+ vectorfield=VGroup(*vectors)
+ vectorfield.scale(1.25)
+
+ fv=[Vector(color=ORANGE),Vector(color=ORANGE),Vector(color=ORANGE),Vector(color=ORANGE),
+ Vector(color=ORANGE),Vector(color=ORANGE),Vector(color=ORANGE),Vector(color=ORANGE),
+ Vector(color=ORANGE),Vector(color=ORANGE),Vector(color=ORANGE),Vector(color=ORANGE),
+ Vector(color=ORANGE),Vector(color=ORANGE),Vector(color=ORANGE),Vector(color=ORANGE),
+ ]
+
+ spaceloc2 = [[1.5,0.5,0.5],[1.5,1,0.5],[1.5,1.5,0.5],[1.5,2,0.5],
+ [1.5,0.5,1],[1.5,1,1],[1.5,1.5,1],[1.5,2,1],
+ [1.5,0.5,1.5],[1.5,1,1.5],[1.5,1.5,1.5],[1.5,2,1.5],
+ [1.5,0.5,2],[1.5,1,2],[1.5,1.5,2],[1.5,2,2]]
+
+ [fv[i].rotate(PI/4,axis=RIGHT) for i in range(1)]
+ [fv[i].rotate(PI/6,axis=OUT) for i in range(16)]
+ [fv[i].rotate(PI/8,axis=DOWN) for i in range(16)]
+ [fv[i].shift(spaceloc2[i]) for i in range(16)]
+ fvfield=VGroup(*fv)
+ fvfield.shift(0.5*IN+2*DOWN)
+
+ flux=TextMobject("Flux through one side of the cube").set_color(ORANGE)
+ flux.shift(3*UP+1.5*LEFT)
+
+
+
+
+
+ self.set_camera_orientation(phi=70 * DEGREES,theta=-75*DEGREES)
self.play(ShowCreation(axes),ShowCreation(axis_label))
- self.play(ShowCreation(cube, run_time=3))
- self.begin_ambient_camera_rotation(rate=-0.2)
- # self.move_camera(phi=150*DEGREES,theta=-45*DEGREES, run_time=3)
+ self.play(ShowCreation(vectorfield))
+ self.add(fvfield)
+ self.begin_ambient_camera_rotation(rate=0.01)
+
+ self.play(ShowCreation(cube, run_time=1))
+
self.wait(1)
self.play(ShowCreation(sq3))
-
self.wait(1)
- self.play(ShowCreation(v1),ShowCreation(n1))
+ self.play(FadeOut(cube))
+ self.play(FadeOut(vectorfield))
+ self.add_fixed_in_frame_mobjects(flux)
+ # self.play(ShowCreation(flux))
self.wait(1)
- self.stop_ambient_camera_rotation()
- self.wait(2)
-
-
- # self.play(Write(t1))
- # self.play(Transform(vg,t1))
- # self.wait(3)
- # self.play(ReplacementTransform(t1,t2))
- # self.wait(3)
- # # self.move_camera(phi=50*DEGREES,theta=-45*DEGREES,run_time=3)
- # self.wait(8)
- # self.move_camera(phi=75 * DEGREES, run_time=3)
- # self.wait(3)
+ self.play(ShowCreation(v1),ShowCreation(n1))
+ self.wait(6)
+ # self.stop_ambient_camera_rotation()
+
diff --git a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/README.md b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/README.md
index df307cd..a1de8b5 100644
--- a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/README.md
+++ b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/README.md
@@ -1,2 +1,10 @@
-**Test**
-![Cube](cube.gif)
+**file1_projection.py**
+![file1_projection](projection.gif)
+**file2_cube.py**
+![file2_cube](cube.gif)
+**file3_cube_sideC.py**
+![file3_cube_sideC](sideC.gif)
+**file4_pauseandponder.py**
+![file4_pauseandponder](pauseandponder.gif)
+**file5_surface.py**
+![file5_surface](file5_surface.gif)
diff --git a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/file5_surface.gif b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/file5_surface.gif
new file mode 100644
index 0000000..27dcac8
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/file5_surface.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/file5_surface.py b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/file5_surface.py
new file mode 100644
index 0000000..3c2e145
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/surface-integrals/file5_surface.py
@@ -0,0 +1,237 @@
+from manimlib.imports import *
+
+class Surf(ThreeDScene):
+
+ CONFIG = {
+ "axes_config": {
+ "x_min": 0,
+ "x_max": 8,
+ "y_min": 0,
+ "y_max": 8,
+ "z_min": 0,
+ "z_max": 6,
+ "a":2 ,"b": 6, "c":1 , "d":6,
+ "axes_shift":-3*OUT + 5*LEFT,
+ "x_axis_config": {
+ "tick_frequency": 1,
+ # "include_tip": False,
+ },
+ "y_axis_config": {
+ "tick_frequency": 1,
+ # "include_tip": False,
+ },
+ "z_axis_config": {
+ "tick_frequency": 1,
+ # "include_tip": False,
+ },
+ "num_axis_pieces": 1,
+ },
+ "default_graph_style": {
+ "stroke_width": 2,
+ "stroke_color": WHITE,
+ },
+ "default_surface_config": {
+ "fill_opacity": 0.5,
+ "checkerboard_colors": [LIGHT_GREY],
+ "stroke_width": 0.5,
+ "stroke_color": WHITE,
+ "stroke_opacity": 0.5,
+ },
+ "Func": lambda x,y: 2+y/4+np.sin(x)
+ }
+
+
+ def construct(self):
+
+ self.setup_axes()
+ self.set_camera_orientation(distance=35,
+ phi=80 * DEGREES,
+ theta=-80 * DEGREES,
+ )
+
+ fn_text=TextMobject("$S$").set_color(BLUE)
+ self.add_fixed_in_frame_mobjects(fn_text)
+ fn_text.to_edge(TOP,buff=MED_SMALL_BUFF)
+
+ R=TextMobject("D").set_color(BLACK).scale(3)
+ R.move_to(self.axes.input_plane,IN)
+ self.add(R)
+
+ #get the surface
+ surface= self.get_surface(
+ self.axes, lambda x , y:
+ self.Func(x,y)
+ )
+ surface.set_style(
+ fill_opacity=0.8,
+ fill_color=YELLOW,
+ stroke_width=0.8,
+ stroke_color=WHITE,
+ )
+
+
+ self.begin_ambient_camera_rotation(rate=0.05)
+ self.play(Write(surface))
+ # self.play(LaggedStart(ShowCreation(surface)))
+
+ self.get_lines()
+ # self.play(FadeIn(self.axes.input_plane))
+ self.wait(2)
+ self.stop_ambient_camera_rotation()
+ self.wait(1)
+
+ def get_surface(self,axes, func, **kwargs):
+ config = {
+ "u_min": axes.c,
+ "u_max": axes.d,
+ "v_min": axes.a,
+ "v_max": axes.b,
+ "resolution": (
+ (axes.y_max - axes.y_min) // axes.y_axis.tick_frequency,
+ (axes.x_max - axes.x_min) // axes.x_axis.tick_frequency,
+ ),
+ }
+
+ config.update(self.default_surface_config)
+ config.update(kwargs)
+ return ParametricSurface(
+ lambda x,y : axes.c2p(
+ x, y, func(x, y)
+ ),
+ **config
+ )
+
+ def get_lines(self):
+ axes = self.axes
+ labels=[axes.x_axis.n2p(axes.a), axes.x_axis.n2p(axes.b), axes.y_axis.n2p(axes.c),
+ axes.y_axis.n2p(axes.d)]
+
+
+ surface_corners=[]
+ for x,y,z in self.region_corners:
+ surface_corners.append([x,y,self.Func(x,y)])
+
+ lines=VGroup()
+ for start , end in zip(surface_corners,
+ self.region_corners):
+ lines.add(self.draw_lines(start,end,"WHITE"))
+
+ for start , end in zip(labels,
+ self.region_corners):
+ # lines.add(self.draw_lines(start,end,"BLUE"))
+ # print (start,end)
+ pass
+ self.play(ShowCreation(lines))
+
+
+ def draw_lines(self,start,end,color):
+ start=self.axes.c2p(*start)
+ end=self.axes.c2p(*end)
+ line=DashedLine(start,end,color=color)
+
+ return line
+
+ def get_three_d_axes(self, include_labels=True, include_numbers=True, **kwargs):
+ config = dict(self.axes_config)
+ config.update(kwargs)
+ axes = ThreeDAxes(**config)
+ axes.set_stroke(width=2)
+
+ if include_numbers:
+ self.add_axes_numbers(axes)
+
+ if include_labels:
+ self.add_axes_labels(axes)
+
+ # Adjust axis orientation
+ axes.x_axis.rotate(
+ 90 * DEGREES, RIGHT,
+ about_point=axes.c2p(0, 0, 0),
+ )
+ axes.y_axis.rotate(
+ 90 * DEGREES, UP,
+ about_point=axes.c2p(0, 0, 0),
+ )
+
+ # Add xy-plane
+ input_plane = self.get_surface(
+ axes, lambda x, t: 1e-5
+ )
+ input_plane.set_style(
+ fill_opacity=0.5,
+ fill_color=TEAL,
+ stroke_width=0,
+ stroke_color=WHITE,
+ )
+
+ axes.input_plane = input_plane
+
+ self.region_corners=[
+ input_plane.get_corner(pos) for pos in (DL,DR,UR,UL)]
+
+ return axes
+
+
+ def setup_axes(self):
+ axes = self.get_three_d_axes(include_labels=True)
+ axes.add(axes.input_plane)
+ axes.scale(1)
+ # axes.center()
+ axes.shift(axes.axes_shift)
+
+ self.add(axes)
+ self.axes = axes
+
+ def add_axes_numbers(self, axes):
+ x_axis = axes.x_axis
+ y_axis = axes.y_axis
+ tex_vals_x = [
+ ("a", axes.a),
+ ("b", axes.b),
+ ]
+ tex_vals_y=[
+ ("c", axes.c),
+ ("d", axes.d)
+ ]
+ x_labels = VGroup()
+ y_labels = VGroup()
+ for tex, val in tex_vals_x:
+ label = TexMobject(tex)
+ label.scale(1)
+ label.next_to(x_axis.n2p(val), DOWN)
+ x_labels.add(label)
+ x_axis.add(x_labels)
+ x_axis.numbers = x_labels
+
+ for tex, val in tex_vals_y:
+ label = TexMobject(tex)
+ label.scale(1.5)
+ label.next_to(y_axis.n2p(val), LEFT)
+ label.rotate(90 * DEGREES)
+ y_labels.add(label)
+
+ y_axis.add(y_labels)
+ y_axis.numbers = y_labels
+
+ return axes
+
+ def add_axes_labels(self, axes):
+ x_label = TexMobject("X")
+ x_label.next_to(axes.x_axis.get_end(), RIGHT)
+ axes.x_axis.label = x_label
+
+ y_label = TextMobject("Y")
+ y_label.rotate(90 * DEGREES, OUT)
+ y_label.next_to(axes.y_axis.get_end(), UP)
+ axes.y_axis.label = y_label
+
+ z_label = TextMobject("Z")
+ z_label.rotate(90 * DEGREES, RIGHT)
+ z_label.next_to(axes.z_axis.get_zenith(), RIGHT)
+ axes.z_axis.label = z_label
+ for axis in axes:
+ axis.add(axis.label)
+ return axes
+ ######Code_by_Somnath_Pandit_https://github.com/panditsomnath10016git#########
+
+
diff --git a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/README.md b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/README.md
index e69de29..2166a79 100644
--- a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/README.md
+++ b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/README.md
@@ -0,0 +1,6 @@
+**file1_3D_crossproduct.py**
+![file1_3D_crossproduct](file1_3D_crossproduct.gif)
+**file2_cylindrical_coordinates.py**
+![file2_cylindrical_coordinates](file2_cylindrical_coordinates.gif)
+**file2_spherical_coordinates.py**
+![file2_spherical_coordinates](file2_spherical_coordinates.gif)
diff --git a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/file2_cylindrical_coordinates.gif b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/file2_cylindrical_coordinates.gif
index 6dc8b17..e913750 100644
--- a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/file2_cylindrical_coordinates.gif
+++ b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/file2_cylindrical_coordinates.gif
Binary files differ
diff --git a/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/file2_spherical_coordinates.gif b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/file2_spherical_coordinates.gif
new file mode 100644
index 0000000..6dc8b17
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/triple-and-surface-integrals/triple-integrals/file2_spherical_coordinates.gif
Binary files differ