How do you find the integral of sinn(x) if m or n is an integer?

1 Answer
Oct 3, 2016

See below.

Explanation:

ddx(cosxsinn1x)=sinnx+(n1)cos2xsinn2x=
=sinnx+(n1)(1sin2x)sinn2x=
=sinnx(n1)sinnx+(n1)sinn2x=
=nsinnx+(n1)sinn2x so calling

In=sinnxdx we have

In(n1n)In2=1ncosxsinn1x with

I0=x and
I1=cosx

So, with this recurrence equation we can build the response for a given n