12. Techniques of Integration

Find the integral.

${\int }_{}^{}s{e}^{3s}ds$

Find the integral.

${\int }_{}^{}\theta \cos 2\theta d\theta$

Find the integral.

${\int }_{}^{}{x}^2\ln xdx$

Find the indefinite integral.

${\int }_{}^{}{r}^2{e}^{-r}dr$