用分部積分法求不定積分[(lnx)³;/x²;]dx

用分部積分法求不定積分[(lnx)³;/x²;]dx

∫[(lnx)^3/x^2]dx
=-∫(lnx)^3d(1/x)
=-(lnx)^3/x + 3∫[(lnx)^2/x^2 ]dx
=-(lnx)^3/x - 3∫[(lnx)^2d(1/x)
=-(lnx)^3/x - 3(lnx)^2/x - 6∫lnxd(1/x)
=-(lnx)^3/x - 3(lnx)^2/x - 6lnx/x + 6∫(1/x^2)dx
=-(lnx)^3/x - 3(lnx)^2/x - 6lnx/x - 6/x + C