1 files changed, 78 insertions, 0 deletions
diff --git a/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file5_level_surface.py b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file5_level_surface.py
new file mode 100644
index 0000000..8052676
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/multivariable-functions-and-paritial-derivatives/scalar-functions/file5_level_surface.py
@@ -0,0 +1,78 @@
+from manimlib.imports import *
+
+class LevelSurface(ThreeDScene):
+    def construct(self):
+        axes = ThreeDAxes() 
+
+        surface_0 = ParametricSurface(
+            lambda u, v: np.array([
+                u*np.cos(v),
+                u*np.sin(v),
+                (u*u*np.cos(v)*np.cos(v))-(u*np.sin(v)/5)+0
+            ]),u_min=-1,u_max=1,v_min=0,v_max=2*PI,checkerboard_colors=[RED_C, RED_E],
+            resolution=(15, 32)).scale(1)
+
+        k_0 = TextMobject("K = 0", color = RED_C).scale(0.7)
+
+        surface_1 = ParametricSurface(
+            lambda u, v: np.array([
+                u*np.cos(v),
+                u*np.sin(v),
+                (u*u*np.cos(v)*np.cos(v))-(u*np.sin(v)/5)+1
+            ]),u_min=-1,u_max=1,v_min=0,v_max=2*PI,checkerboard_colors=[GREEN_C, GREEN_E],
+            resolution=(15, 32)).scale(1)
+        
+        k_1 = TextMobject("K = 1", color = GREEN_C).scale(0.7)
+
+        surface_2 = ParametricSurface(
+            lambda u, v: np.array([
+                u*np.cos(v),
+                u*np.sin(v),
+                (u*u*np.cos(v)*np.cos(v))-(u*np.sin(v)/5)+2
+            ]),u_min=-1,u_max=1,v_min=0,v_max=2*PI,checkerboard_colors=[YELLOW_C, YELLOW_E],
+            resolution=(15, 32)).scale(1)
+
+        k_2 = TextMobject("K = 2", color = YELLOW_C).scale(0.7)
+
+        func = TextMobject(r"$w = g(x,y,z)$", r"$= z - f(x,y)$", r"$z-x^2+y/5 = K$")
+        func.set_color_by_gradient(RED, ORANGE, YELLOW, GREEN, BLUE, PURPLE)
+
+        self.set_camera_orientation(phi=90 * DEGREES, theta = 90*DEGREES)
+        self.begin_ambient_camera_rotation(rate=0.3)
+
+
+        self.add(axes)
+        
+        axis = TextMobject(r"X",r"Y",r"Z")
+        axis[0].move_to(6*RIGHT)
+        axis[1].move_to(6*UP)
+        axis[2].move_to(3.7*UP)
+
+        self.add_fixed_in_frame_mobjects(axis[2])
+        self.add_fixed_orientation_mobjects(axis[0])
+        self.add_fixed_orientation_mobjects(axis[1])
+
+        self.play(Write(surface_0))
+        self.add_fixed_in_frame_mobjects(k_0)
+        k_0.move_to(np.array([1.4*RIGHT ]))
+
+        self.play(Write(surface_1))
+        self.add_fixed_in_frame_mobjects(k_1)
+        k_1.move_to(np.array([1.4*RIGHT + 1*UP]))
+    
+        self.play(Write(surface_2))
+        self.add_fixed_in_frame_mobjects(k_2)
+        k_2.move_to(np.array([1.4*RIGHT + 2*UP]))
+        self.wait()
+
+        self.add_fixed_in_frame_mobjects(func)
+        func[0].move_to(np.array([4.5*LEFT + 3*UP]))
+        func[1].move_to(np.array([4.5*LEFT + 2.5*UP]))
+        func[2].move_to(np.array([4.5*LEFT + 2*UP]))
+
+        self.wait(3)
+        self.move_camera(phi=60 * DEGREES,run_time=3)
+        self.wait(2)
+
+
+     
+\ No newline at end of file