# Math Help - Sin reduction formula!

1. ## Sin reduction formula!

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

2. 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.