Question: Evaluate the integrals below.

a- \(\int{\frac{x}{{{\left( 1+{{x}^{2}} \right)}^{2}}}dx}\)

b- \(\int{\cos \left( 3\theta \right){{\sin }^{10}}\left( 3\theta \right)d\theta }\)

c- \(\int\limits_{0}^{2}{{{\left( 1+{{x}^{2}} \right)}^{2}}dx}\)