(1) Evaluate `int cos^5 x dx`.

Hint: Express `cos^4 x` in terms of `sin x`. Then use the substitution `u=sin x`. Back substitute to write your soluton in terms of `x`.

solution `=` `+ C`
 

(2) Evaluate `int cos^2 x dx`.

Hint: Use the half-angle identity `cos^2 x = 1/2 (1+cos 2x)`.

solution `=` `+ C`