Question

How do you find the derivative of `f(z)=e^z(cosz)`?

Answer 1

`f'(z)=e^z(cosz-sinz)`

Explanation:

use product rule:

`f'(z)=d/dz(e^z)*cosz+d/dz(cosz)*e^z`

`f'(z)=e^z*cosz-sinz*e^z`

`f'(z)=e^z(cosz-sinz)`