In how many different ways can you find answers to the following integrals?

\(\displaystyle {\int_{0}^{\pi} \cos 2x \, dx}\)

\(\displaystyle {\int_{0}}^{\frac{\pi}{2}} \sin^2 x \, dx\)

\(\displaystyle {\int_{-1}^{1}} \arcsin x \, dx\)

\(\displaystyle {\int_{-1}^{1}} \arccos x \, dx\)