∫ (3+4x)/x3 dx
∫ ((3+4x)x3)dx= ∫ ((3/x3)+(4x)/x3)dx= ∫ (3·x–3+4x–2)dx= =3 ∫ (x–3)dx+4 ∫ (x–2)dx=3·(x–3+1/(–3+1)+4·(x–2+1/(–2+1))+C= =–3/(2x2)–4/x+C.