Evaluate: `intxsin2x\ dx`

Explanation

Given integral
`intxsin2x\ dx`
Differentiating by parts
`intxsin2x\ dx`
`=x int sin 2x-int (dx)/(dx)(int sin2xdx)dx`
`=x/2 cos2x-1/2int cos 2x dx`
`=x/2 cos2x+1/4 sin 2x+c`