r_1 = 1 (slider from 0 to 5, step 0.1)
C_1 = (1, 0)
P = (0.8109449360181656, 0.5482982381101674)
C_f = (0, 0)
a = Ray(C_f, P)
c = Circle(C_1, r_1)
A, P_1 = Intersect(c, a)