y = f(x)

y = f^{-1}(x) 

y = x

A = (1, 5)
B = (-3, 5)
g(x) = 2^(x)
f(x) = x
C = Point(g)
D = Point(f)
E = Point(f)
a = Line(D, E)
C' = Mirror(C, a)
b = Segment(C, C')