Question

$$= \cos ( \frac { \cos r } { r } ) + \pi ^ { \pi }$$

Evaluate

$\cos(\frac{\cos(r)}{r})+\pi ^{\pi }$

Differentiate w.r.t. r

$\frac{\sin(\frac{\cos(r)}{r})\left(r\sin(r)+\cos(r)\right)}{r^{2}}$