{"action":"created","issue":{"url":"https://api.github.com/repos/sympy/sympy/issues/10702","repository_url":"https://api.github.com/repos/sympy/sympy","labels_url":"https://api.github.com/repos/sympy/sympy/issues/10702/labels{/name}","comments_url":"https://api.github.com/repos/sympy/sympy/issues/10702/comments","events_url":"https://api.github.com/repos/sympy/sympy/issues/10702/events","html_url":"https://github.com/sympy/sympy/issues/10702","id":137023476,"number":10702,"title":"Expression tan(x)*cot(x) is not constant","user":{"login":"rpisarev","id":370851,"avatar_url":"https://avatars.githubusercontent.com/u/370851?v=3","gravatar_id":"","url":"https://api.github.com/users/rpisarev","html_url":"https://github.com/rpisarev","followers_url":"https://api.github.com/users/rpisarev/followers","following_url":"https://api.github.com/users/rpisarev/following{/other_user}","gists_url":"https://api.github.com/users/rpisarev/gists{/gist_id}","starred_url":"https://api.github.com/users/rpisarev/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/rpisarev/subscriptions","organizations_url":"https://api.github.com/users/rpisarev/orgs","repos_url":"https://api.github.com/users/rpisarev/repos","events_url":"https://api.github.com/users/rpisarev/events{/privacy}","received_events_url":"https://api.github.com/users/rpisarev/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":10,"created_at":"2016-02-28T07:44:10Z","updated_at":"2016-03-11T09:01:58Z","closed_at":null,"body":"In [11]: a = tan(x)*cot(x)\r\n\r\nIn [12]: a.is_constant()\r\nOut[12]: True\r\n\r\nThat's wrong"},"comment":{"url":"https://api.github.com/repos/sympy/sympy/issues/comments/195267592","html_url":"https://github.com/sympy/sympy/issues/10702#issuecomment-195267592","issue_url":"https://api.github.com/repos/sympy/sympy/issues/10702","id":195267592,"user":{"login":"ankyAS","id":10551109,"avatar_url":"https://avatars.githubusercontent.com/u/10551109?v=3","gravatar_id":"","url":"https://api.github.com/users/ankyAS","html_url":"https://github.com/ankyAS","followers_url":"https://api.github.com/users/ankyAS/followers","following_url":"https://api.github.com/users/ankyAS/following{/other_user}","gists_url":"https://api.github.com/users/ankyAS/gists{/gist_id}","starred_url":"https://api.github.com/users/ankyAS/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ankyAS/subscriptions","organizations_url":"https://api.github.com/users/ankyAS/orgs","repos_url":"https://api.github.com/users/ankyAS/repos","events_url":"https://api.github.com/users/ankyAS/events{/privacy}","received_events_url":"https://api.github.com/users/ankyAS/received_events","type":"User","site_admin":false},"created_at":"2016-03-11T09:01:58Z","updated_at":"2016-03-11T09:01:58Z","body":"I think @rpisarev is correct as the tan and cot are discontinous function and the value of tanx is not defined at (pi/2)*k.So it should not always be 1.\r\n@thisch  writing tan(x) in terms of  sin(x) and cos(x) will led to value being undefined at (pi/2) while both sin(x) and cos(x) are defined at pi/2"}}