c = CurveCartesian((2 * cos(t)), (2 * sin(t)), t, 0, 6.283185307179586)
s = 1.1 (slider from 0 to 3, step 0.1)
daen = CurveCartesian((cosh(s) * sin(t)), (sinh(s) * cos(t)), t, 0, 6.283185307179586)
u = 0.7853981633974483
r = 2.443460952792061 rad (slider from 0 to 6.283185307179586, step 0.08726646259971647)
a: (1, r)
r1 = 1.4142135623730951