Question

xe^x/(1+e^x)^2的不定积分,这个真解决不了

Answer 1

简单计算一下即可，答案如图所示

Answer 2

分部积分:
=-亅xd1/(1+e^x)
=-x/(1+e^x)+亅dx/(1+e^x)
=-x/(1+e^x)+
亅e^(-x)dx/(1+e^(-x))
=-x/(1+e^x)-ln(1+e^(-x))+C