# How to solve fourier series integrals

#### gutto@Mac

Joined Nov 26, 2007
1
Ive tryin to solve the fourier series integrals but they are really confusing.....
when we find "an" and "bn" we solve integrals how do we solve them completely to get the answer...my book has only shown the an formula deivation and then it says
"by long integration we got following answer...."
Any tips on that

#### Papabravo

Joined Feb 24, 2006
14,233
There are two tools that are handy in integration:
1. Integration by Parts
2. Trigonometric Identities
My favorite is
cos(n+1)θ + cos(n-1)θ = 2cos(θ)cos(nθ)