Kurvenschar
Author: Marcus Sopicki

f _k(x) = x^4-\,k\cdot x^2

k = 3 (slider from 0.1 to 5, step 0.1)
f(x) = x^(4) - (k * x^(2))
E_1, E_2, E_3 = Extremum(f)
W_1, W_2 = TurningPoint(f)
N_1, N_2, N_3 = Root(f)