2∫（lnx）/（x^2）dx =-2∫（lnx)d(1/x)=-2（lnx）/x+2∫1/x^2dx =-2（lnx）/x-2/x+C ∫（lnx）^2/（x^2）dx=-∫（lnx）^2d(1/x) =-(lnx）^2/x+2∫（lnx）/（x^2）dx =-(lnx）^2/x-2（lnx）/x-2/x+C
