# Integral of $\int \frac{\cos^5 x}{ \sqrt {\sin x}} dx$

I am not even going to show my work because I have accomplished nothing attempting this problem. I have absolutely no idea what to do.

$$\int \frac{\cos^5 x}{ \sqrt {\sin x}}\, dx$$

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It's an application of the rule of thumb needed for this and several of your previous questions: If you have $\cos$ to an odd power upstairs in the integrand, try factoring out one $\cos$ term, write the other $\cos$ terms in terms of $\sin$, and let $u=\sin x$. –  David Mitra Jun 3 '12 at 15:56
@DavidMitra I have memorized that rule because it is in a table in my book. I know how to do simple problems like that but that was not my problem. –  user138246 Jun 3 '12 at 15:57
This silly system should tell me that someone else is editing the post at the same time. –  Gigili Jun 3 '12 at 15:58

Write $\cos^{5}(x) = (1-\sin^{2}{x})^{2} \cdot \cos{x}$ and then put $t =\sin{x}$.