Simplifying complex numbers

1. Oct 1, 2008

kring_c14

Our professor asks us to evaluate the following. So, i am assuming that he asks us to simplify the equation. Ive included my computation. I am quite stuck. I don't know if im simplifying or just complicating the problem..please help!me!

Ive used Euler formula..and then im stuck..

here's what i did