Question

∫ (ln x)/x^3 dx 他舅

Answer 1

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