e = -0.2 (slider from -10 to 10, step 0.1)
a = 1 (slider from -10 to 10, step 0.1)
b = -4 (slider from -10 to 10, step 0.1)
c = 2 (slider from -10 to 10, step 0.1)
d = 3.1 (slider from -10 to 10, step 0.1)
f(x) = (a * x^(4)) + (b * x^(3)) + (c * x^(2)) + (d * x) + e
Max, Min, A = Extremum(f)
Inf_1, Inf_2 = TurningPoint(f)
zh_1, zh_2, zh_3, zh_4 = Root(f)