evaluate the integral by using integration by parts

2. Originally Posted by yang03265

evaluate the integral by using integration by parts
Recall that the IBP formula is $\int u\,dv=uv-\int v\,du$

Let $u=x$ and $\,dv=\cos^2x\,dx$.

I leave the computation work for you to do, but take note that $\cos^2x=\tfrac{1}{2}\left(1+\cos\!\left(2x\right)\ right)$.

Can you try to take it from here?