高数 分部积分法

2025-04-24 03:48:04
推荐回答(1个)
回答1:

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