f(x) = a x^3 + b x^2 + c x + d

d = 2 (slider from -5 to 5, step 0.1)
a = 0.5 (slider from -5 to 5, step 0.1)
b = 0 (slider from -5 to 5, step 0.1)
c = -1.2 (slider from -5 to 5, step 0.1)
f(x) = a x^(3.000000000000000) + b x^(2.000000000000000) + c x + d
I = TurningPoint(f)
f'' = Derivative(f, 2.000000000000000)
R_1, R_2, R_3 = Root(f)
E_2, E_1 = Extremum(f)
f' = Derivative(f)
a_1 = Segment(E_2, (x(E_2), 0.000000000000000))
b_1 = Segment(E_1, (x(E_1), 0.000000000000000))
c_1 = Segment(I, (x(I), 0.000000000000000))
T2: "f(x) = " + (Polynomial[f])