# Help with trigonometric integral

1. Sep 19, 2011

### miglo

1. The problem statement, all variables and given/known data
$$\int_{\frac{5\pi}{6}}^{\pi}\frac{\cos^{4}x}{\sqrt{1-\sin{x}}}dx$$

2. Relevant equations
$$\cos^{2}x=\frac{1+\cos{2x}}{2}$$

3. The attempt at a solution
i used the above equation, then expanded it all out and multiplied by the denominator and hoped i would then be able to do a simple substitution that would give me an antiderivative after integrating but that hasn't been working for me
any ideas?

2. Sep 20, 2011

### Hootenanny

Staff Emeritus
A relatively straightforward method involves a series of substitutions. I would start with $u=1-\sin x$