1 files changed, 29 insertions, 0 deletions
diff --git a/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file6_f(x,y)=(y-x)(1-2x-3y).py b/FSF-2020/calculus-of-several-variables/approximations-and-optimizations/Critical-Points/file6_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/file6_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)