The integral is given as,
I= ∫ xlog2xdx
Use integration by parts. Consider log2xas first function and xas second function.
I= ∫ xlog2xdx =log2x ∫ xdx − ∫ ( d dx log2x ∫ xdx )dx
On integrating, we get
I=log2x× x 2 2 − ∫ 2 2x ( x 2 2 )dx = x 2 log2x 2 − 1 2 ∫ xdx I= x 2 log2x 2 − x 2 4 +C