# How to solve this definite integral

1. Feb 24, 2012

### zhiyuanhou

Hi everyone, when I was dealing with a physics problem, I find a definite integral and I cannot solve it.
$\int_{0}^{2\pi}$$\frac{1}{(a+cosx)^{2}}$dx
a is constant.
Thank you!

2. Feb 24, 2012

### micromass

3. Feb 24, 2012

### zhiyuanhou

ha ha! Weierstrass substitution is well! Thank you!