{"action":"created","issue":{"url":"https://api.github.com/repos/sympy/sympy/issues/10445","labels_url":"https://api.github.com/repos/sympy/sympy/issues/10445/labels{/name}","comments_url":"https://api.github.com/repos/sympy/sympy/issues/10445/comments","events_url":"https://api.github.com/repos/sympy/sympy/issues/10445/events","html_url":"https://github.com/sympy/sympy/issues/10445","id":128326004,"number":10445,"title":"Improper integral does not evaluate","user":{"login":"bolverk","id":5267267,"avatar_url":"https://avatars.githubusercontent.com/u/5267267?v=3","gravatar_id":"","url":"https://api.github.com/users/bolverk","html_url":"https://github.com/bolverk","followers_url":"https://api.github.com/users/bolverk/followers","following_url":"https://api.github.com/users/bolverk/following{/other_user}","gists_url":"https://api.github.com/users/bolverk/gists{/gist_id}","starred_url":"https://api.github.com/users/bolverk/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/bolverk/subscriptions","organizations_url":"https://api.github.com/users/bolverk/orgs","repos_url":"https://api.github.com/users/bolverk/repos","events_url":"https://api.github.com/users/bolverk/events{/privacy}","received_events_url":"https://api.github.com/users/bolverk/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2016-01-23T12:26:34Z","updated_at":"2016-01-23T16:01:32Z","closed_at":null,"body":"The integral of 1/(exp(x)+1) from 0 to infinity should give log(2), but sympy 0.7.6.1 produces a NaN\r\n\r\n```python\r\nfrom sympy import oo, exp, Symbol, integrate\r\nx = Symbol('x')\r\nintegrate(1/(1+exp(x)),(x,0,oo))\r\n```"},"comment":{"url":"https://api.github.com/repos/sympy/sympy/issues/comments/174196189","html_url":"https://github.com/sympy/sympy/issues/10445#issuecomment-174196189","issue_url":"https://api.github.com/repos/sympy/sympy/issues/10445","id":174196189,"user":{"login":"jksuom","id":6929119,"avatar_url":"https://avatars.githubusercontent.com/u/6929119?v=3","gravatar_id":"","url":"https://api.github.com/users/jksuom","html_url":"https://github.com/jksuom","followers_url":"https://api.github.com/users/jksuom/followers","following_url":"https://api.github.com/users/jksuom/following{/other_user}","gists_url":"https://api.github.com/users/jksuom/gists{/gist_id}","starred_url":"https://api.github.com/users/jksuom/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jksuom/subscriptions","organizations_url":"https://api.github.com/users/jksuom/orgs","repos_url":"https://api.github.com/users/jksuom/repos","events_url":"https://api.github.com/users/jksuom/events{/privacy}","received_events_url":"https://api.github.com/users/jksuom/received_events","type":"User","site_admin":false},"created_at":"2016-01-23T16:01:32Z","updated_at":"2016-01-23T16:01:32Z","body":"It appears that the integrator does not recognize improper integrals as limits. It finds the correct indefinite integral ``x - log(exp(x) + 1)``, but, instead of taking the limit ``x -> oo`` it tries to assign the value ``oo`` to ``x`` on [this line](https://github.com/sympy/sympy/blob/master/sympy/integrals/integrals.py#L523) and arrives at ``nan``."}}