Integration Problem: Solve sin^3Φ from 0 to 2π

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It seems quite simple actually. But I'm still stuck:

\int_{0} ^ {2\Pi} sin^3\Phi d\Phi

Can anyone help?
 
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That's a standard "sine or cosine to an odd power" integral.
sin^3\Phi d\Phi= (sin^2\Phi)(sin\Phi)d\Phi= (1- cos^2\Phi)(sin \Phi d\Phi)
See any simple substitution you can use?
 
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