f(x) = x^3 - 4·x^2 - x + 4
F(x) = 1/4·x^4 - 4/3·x^3 - 1/2·x^2 + 4·x
Nullstellen f(x) = 0
x^3 - 4·x^2 - x + 4 = 0 --> x = 4 ∨ x = -1 ∨ x = 1
∫ (-1 bis 1) f(x) dx = F(1) - F(-1) = 29/12 - (- 35/12) = 16/3
∫ (1 bis 4) f(x) dx = F(4) - F(1) = - 40/3 - (29/12) = - 63/4
A = 16/3 + 63/4 = 253/12 = 21.08 FE