lengte = 4 (slider from 0 to 8, step 0.1)
N = (2, -2)
A = (18, -2)
c = Circle(N, lengte)
i = Line(N, A)
B = Intersect(c, i, 2)
U = (-5, 3)
stap = 11 (slider from 0 to 11, step 1)
f = Segment(N, B)
g = OrthogonalLine(N, i)
P, Q = Intersect(c, g)
h = Segment(P, N)
r = Line(P, f)
s = Line(B, h)
T = Intersect(r, s)
α = Angle(B, N, P)
t = Segment(T, B)
a = Segment(T, P)
δ = Angle(P, T, B)
β = Angle(N, B, T)
γ = Angle(N, P, T)
C = Intersect(c, i, 1)