f(x) = 1/4·(x + 2)·(x - 1)^2 = 0.25·x^3 - 0.75·x + 0.5
g(x) = 0.5
d(x) = f(x) - g(x) = 0.25·x^3 - 0.75·x = 0 --> x = ±√3 ∨ x = 0 (Beachte hier die Achsensymmetrie)
D(x) = 0.0625·x^4 - 0.375·x^2
A = 2·|∫ (0 bis √3) (0.25·x^3 - 0.75·x)| dx = 2·|D(√3)| dx = 9/8