# Sin reduction formula!

• April 19th 2010, 11:47 AM
usagi_killer
Sin reduction formula!
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How can I get rid of the $\sin^{n-1}(x)$, because the question says in terms of $\sin^{n-2}(x)$
• April 19th 2010, 01:45 PM
Opalg
Quote:

Originally Posted by usagi_killer
How can I get rid of the $\sin^{n-1}(x)$, because the question says in terms of $\sin^{n-2}(x)$

It doesn't say "in terms of $\sin^{n-2}(x)$", it says "in terms of $I(n-2)$", and that is what you have done. You're allowed to keep the term $-\frac1n\sin^{n-1}(x)\cos(x)$ in the answer, though perhaps the question could have been worded better, to make that clearer.