Re: Integrate[e/(1+Exp[e]),{e,ei,Infinity}]
- To: mathgroup at yoda.physics.unc.edu
- Subject: Re: Integrate[e/(1+Exp[e]),{e,ei,Infinity}]
- From: withoff
- Date: Fri, 11 Dec 92 15:08:33 CST
> Integrate[e/(1+Exp[e]),{e,ei,Infinity}] > this fermintegral of order 1 results in RecursionLimit errors. > The indefinite integral can be found without any problems. > Any ideas how to change the situation?? > > Michael Trott > > trott at physik.tu-ilmenau.de If the indefinite integral works, it can probably be used to compute the definite integral. The built-in Limit function can't handle the limit at Infinity, but the package Calculus`Limit` can. In[1]:= f = Integrate[e/(1+Exp[e]),e] 2 e e e Out[1]= -- - e Log[1 + E ] - PolyLog[2, -E ] 2 In[2]:= << Calculus`Limit` In[3]:= Limit[f, e -> Infinity] 2 Pi Out[3]= --- 6 In[4]:= Limit[f, e -> ei] 2 ei ei ei Out[4]= --- - ei Log[1 + E ] - PolyLog[2, -E ] 2 In[5]:= %% - % 2 2 -ei Pi ei ei Out[5]= ---- + --- + ei Log[1 + E ] + PolyLog[2, -E ] 2 6 Dave Withoff withoff at wri.com