Dreieck

a = 1.5 (slider from -2 to 2, step 0.1)
f(x) = (1 / 4 * x^(4)) - ((1 / 2 * a) * x^(3))
A_{1}, B = Extremum(f)
g(x, k) = (1 / 4 * x^(4)) - ((1 / 2 * k) * x^(3))
A_{2}, A = TurningPoint(f)
A_{4} = (0, 0)
D, E, C = Root(f)
t2 = Tangent(C, f)
F, G = Root(f)
d, g_1, f_1, a_1 = Polygon(F, A, G)
b = false
Text1: "f_{" + a + "}"