note 115643 added to function.atan

Contrary to the current description, it should hold y == tan(atan(y)) for ALL y. However, x == atan(tan(x)) only holds for those x which are in the range of atan, which are those x with -pi/2 < x < pi/2. Of course, those equalities are limited by precision. On my machine tan(atan(1000)) returns 1000.0000000001. atan(tan(0)) returns 0 (correct). atan(tan(M_PI)) returns -1.2246467991474E-16 instead of 0. ---- Server IP: 72.52.91.14 Probable Submitter: 2a02:810b:8500:494:21e:8cff:fe1c:7c9f ---- Manual Page -- http://php.net/manual/en/function.atan.php Edit -- https://master.php.net/note/edit/115643 Del: integrated -- https://master.php.net/note/delete/115643/integrated Del: useless -- https://master.php.net/note/delete/115643/useless Del: bad code -- https://master.php.net/note/delete/115643/bad+code Del: spam -- https://master.php.net/note/delete/115643/spam Del: non-english -- https://master.php.net/note/delete/115643/non-english Del: in docs -- https://master.php.net/note/delete/115643/in+docs Del: other reasons-- https://master.php.net/note/delete/115643 Reject -- https://master.php.net/note/reject/115643 Search -- https://master.php.net/manage/user-notes.php