t = 3.6 (slider from 0 to 20, step 0.1)
C: (4.0 * cos(t), 4.0 * sin(t))
A = Intersect(xAxis, yAxis)
f(x) = 4.0 * sin(x)
g(x) = 4.0 * cos(x)
D: (t, 4.0 * sin(t))
G: (t, 4.0 * cos(t))
B = Point(f)
c = Circle(B, C)