n∫(0->1) xf'(2x) dx =∫(0->2) xf'(x) dxletx=2udx = 2dux=0, u=0x=2, u=1∫(0->2) xf'(x) dx=∫(0->1) 2u .f'(2u) (2du)=4∫(0->1) u .f'(2u) du=4∫(0->1) x .f'(2x) dx=>n=4
