g(x) = tan(x)
r = -7.6 (slider from -10 to 10, step 0.1)
g' = Derivative(g)
text1: "y = " + g + ""
Prmtrc = CurveCartesian(t + r / (1 + g'(t)^(2))^(0.5), g(t) + g'(t) * r / (1 + g'(t)^(2))^(0.5), t, -15, 15)