f: y = sin(x)^(2)
g: y = cos(x)^(2)
A = Intersect(f, g, (0.7853981633971714, 0.4999999999997231))
h = Tangent(A, g)
i = Tangent(A, f)
B = Point(i)
C = Point(h)
α = Angle(B, A, C)