Question

ln(x)的积分怎么求? 如题

Answer 1

∫ ln (x) dx
=x ln (x) -∫ x d [ ln(x) ]
=x ln(x) -∫ x *(1/x) dx
=x ln (x) -∫ dx
=x ln (x) -x +C,(C为任意常数).
= = = = = = = = =
分部积分法.
∫ dx 即 ∫ 1 dx,即对常数1积分.
不懂追问.