This problem will be solved using the integration by parts method, taking the integrated function as udv which answer is uv-(integration of vdu) : u=x and dv=cos(x) so, du=dx and v=sin(x). We have, xsin(x)-integration(sinxdx), and knowning that the integrate of sinx is: -cos(x)+c (constant), the final answer is: xsin(x)+cos(x)+c.