r(x)

K=(θ, r(θ))

θ

r(θ)

P=(r(θ); θ)

r(θ)

θ

r(x) = If[0.3 ≤ x ≤ 1.3, 3 - x]
θ = 0.55 (slider from -5 to 5, step 0.05)
K: (θ, r(θ))
T: (x(K), 0)
O: (0, 0)
a = Segment(O, T)
b = Segment(K, T)
c = CurveCartesian((r(t) * cos(t)), (r(t) * sin(t)), t, 0.3, 1.3)
P: (r(θ); θ)
d = Segment(P, O)
A = Point(xAxis)
α = Angle(A, O, P)