The chain rule's formula is as follows: F'(g(x)) * g'(x).
f represents the outside function, e^x, and g represents the inside function, sin x. Now one must plug in the functions to this formula.
The derivative of e^x is always e^x, but since it's f'(g(x)), we must plug in the function for g(x) into the x in e^x, giving us e^sinx. Then we must multiply that with the derivative of sinx, which is cosx.
So essentially, the answer will be (cosx)(e^sinx)