parametriche evolvente del cerchio

x = k (cos(t)+ t sin(t))

y = k (sin(t) - t cos(t))

k = 2.3 (slider from -5 to 5, step 0.1)
c = CurveCartesian(k * (cos(t) + t * sin(t)), k * (sin(t) - t * cos(t)), t, 0, 6.28)