Đề bài

Tìm:

a) $\int {{{\left( {3{\rm{x}} - \frac{1}{{{x^2}}}} \right)}^2}dx}$; b) $\int {\left( {7{\rm{x}}\sqrt[3]{x} - \frac{1}{{\sqrt {{x^3}} }}} \right)dx} \left( {x > 0} \right)$;

c) $\int {{{\left( {{3^{2{\rm{x}}}} - 1} \right)}^2}dx}$;    d) $\int {\left( {2 - 3{{\cos }^2}\frac{x}{2}} \right)dx}$.