Easy derivative

differentiation of the function gives : $7e^{\sin \pi}.\cos \pi$

so we know,

$\sin \pi = 0$ and $\cos \pi = -1$

putting these values, we get $\boxed{-7}$

$\begin{aligned} f(x) &=& 7 e^{\sin (x)} \\ f'(x) &=& 7 e^{\sin (x)} \cos (x) \\ f'(\pi) &=& 7 e^{\sin (\pi)} \cos (\pi) = 7 \cdot e^0 \cdot (-1) = \boxed{-7} \end{aligned}$