原式=(-1/2)∫lnxd(1/x^2)
=(-1/2)lnx/x^2+(1/2)∫(1/x^2)dlnx
=(-1/2)lnx/x^2+(1/2)∫(1/x^3)dx
=(-1/2)lnx/x^2+1/(4x^2)+C
=(1-2lnx)/x^2+C