There are probably better solutions, but you can rewrite it like this:

You can then split the original sum into three different sums and use the identity for the two sums that have cosinus terms in them.

Results 1 to 7 of 7

- December 28th 2011, 08:37 AM #1

- December 28th 2011, 10:06 AM #2

- Joined
- Dec 2011
- Posts
- 92
- Thanks
- 7

- December 28th 2011, 06:40 PM #3

- December 29th 2011, 07:53 AM #4

- December 30th 2011, 04:23 AM #5

- December 30th 2011, 06:42 AM #6

- December 30th 2011, 01:08 PM #7