y = cos x

A = Intersect(xAxis, yAxis)
c = Circle(A, 1)
B = (1, 1)
a = Ray(A, B)
C = Intersect(c, a, 1)
b = OrthogonalLine(C, xAxis)
D = Intersect(b, xAxis)
d = Segment(C, D)
α = Angle(xAxis, a)
e = Segment(A, D)