f(x)=Arccos(x)

π

π

g = Function(cos(x), 0, π)
f(x) = cos(x)
h(x) = acos(x)
a: y = x
f_1 = Mirror(f, a)
A: (π, 0)
B: (π, cos(π))
i = Segment(A, B)
C: (0, π)
D: (-1, π)
j = Segment(D, C)