f(x) = 0.5 * x^(3.0) + 2.0 * x^(2.0) + 0.2 * x - 1.0
R_1, R_2, R_3 = Root(f(x))
E_1, E_2 = Extremum(f(x))
t_1 = Tangent(E_1, f(x))
t_2 = Tangent(E_2, f(x))