a = 1 (slider from -5 to 5, step 0.1)
b = 1 (slider from -5 to 5, step 0.1)
a_2 = CurveCartesian(b * t - a * sin(t), a - a * cos(t), t, 0.0, 20.0)
Text1: "x(t) = " + b + " t - " + a + " sin(t)"
Text2: "y(t) = " + a + " - " + a + " cos(t)"