I.3.1.68 Indefinite Integrals

Condition: Find vague integrals. 1) \ (\ int \ frac {x^{4} d x} {x^{2} +1} \) 2) \ (\ int \ frac {x^} d x} {\ left (x^{2} +2 x-3 \ right) (x+1)} \); 3) \ (\ int \ sin ^{2} x \ cos x d x \)