$\displaystyle \int sin(x)cos(nx)dx$ where n is a positive entire

Thank's.

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- Jun 6th 2011, 07:58 AMhurzTrigonometric integral
$\displaystyle \int sin(x)cos(nx)dx$ where n is a positive entire

Thank's. - Jun 6th 2011, 08:01 AMGeneral
$\displaystyle \displaystyle sin(A)cos(B)=\frac{sin(A-B) + sin(A+B)}{2}$

- Jun 6th 2011, 08:03 AMFernandoRevilla
Use $\displaystyle 2\sin mx\cos nx=\sin (m+n)x+\sin (m-n)x$ .

Edited: Sorry, I didn't see**General**'s post. - Jun 6th 2011, 08:07 AMAckbeet
You could also integrate by parts twice and solve for the original integral.