How do you integrate int xcos(2x) by integration by parts method?

1 Answer
Aug 19, 2016

1/4(2x*sin2x+cos2x)+C.

Explanation:

Let I=intxcos2xdx

We use the Rule of Integration by Parts, which is,

intuvdx=uintvdx-int[(du)/dxintvdx]dx

We take,

u=x, so (du)/dx=1; & v=cos2x, so, intvdx=(sin2x)/2.

Hence, I=x/2*sin2x-1/2intsin2xdx

=x/2*sin2x-1/2((-cos2x)/2)

=1/4(2x*sin2x+cos2x)+C.

Enjoy Maths.!