1. Integration

How do i integrate cos4xcosx ?
i used cos4x=2cos(^2)2x - 1
i dont know how to proceed.

2. Originally Posted by kandyfloss
How do i integrate cos4xcosx ?
i used cos4x=2cos(^2)2x - 1
i dont know how to proceed.
Use the product to sum identitety

List of trigonometric identities - Wikipedia, the free encyclopedia