r=2cos(3θ)
Author: Bekki George

θ = 0 rad (slider from 0 to 6.283185307179586, step 0.0017)
a = CurveCartesian(2.0 * cos(3.0 * t) * cos(t), 2.0 * cos(3.0 * t) * sin(t), t, 0.0, 6.28)
B = Point(a)
A: (2.0 * cos(3.0 * θ) * cos(θ), 2.0 * cos(3.0 * θ) * sin(θ))
b = Segment(A, B)