t = 2.6352220400000004 (slider from -9.42477796 to 9.42477796, step 0.01)
M_t: (cos(t), sin(t))
O = (0, 0)
I = (1, 0)
J = (0, 1)
C = Circle(O, I)
α = Angle(I, O, M_t)
a = Segment(O, M_t)
P_t: (t, sin(t))
Q_t: (t, cos(t))