1 files changed, 54 insertions, 0 deletions
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)
+        
+        
+        
+        
+        
+