## maxima-bugs

 [Maxima-bugs] [ maxima-Bugs-1741705 ] integrate(1/(sin(x)^2+1), x, 0, 8) wrong From: SourceForge.net - 2007-06-22 15:59:28 ```Bugs item #1741705, was opened at 2007-06-22 11:59 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1741705&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core - Integration Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Raymond Toy (rtoy) Assigned to: Nobody/Anonymous (nobody) Summary: integrate(1/(sin(x)^2+1),x,0,8) wrong Initial Comment: integrate(1/(sin(x)^2+1),x,0,8) returns sqrt(2)/2*atan(sqrt(2)*tan(8)) + %pi/sqrt(2) This is not right. But integrate(1/(sin(x)^2+1),x,0,5*%pi/2) returns 5*sqrt(2)*%pi/4, which is probably correct according to quad_qags. This latter integral works because intsc1 notices that the interval length is a rational multiple of %pi and breaks up the integral. However, for the former integral, intsc1 gives up because the interval length is not a multiple of %pi. Since we now have a floor function that works well, we should try to extend intsc1 to accept all numeric limits. This issue affects all integrals of trig functions that are handled by intsc1. See also the related bug 1552789. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1741705&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-1741705 ] integrate(1/(sin(x)^2+1), x, 0, 8) wrong From: SourceForge.net - 2007-07-12 01:53:59 ```Bugs item #1741705, was opened at 2007-06-22 11:59 Message generated for change (Comment added) made by jul059 You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1741705&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core - Integration Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Raymond Toy (rtoy) Assigned to: Nobody/Anonymous (nobody) Summary: integrate(1/(sin(x)^2+1),x,0,8) wrong Initial Comment: integrate(1/(sin(x)^2+1),x,0,8) returns sqrt(2)/2*atan(sqrt(2)*tan(8)) + %pi/sqrt(2) This is not right. But integrate(1/(sin(x)^2+1),x,0,5*%pi/2) returns 5*sqrt(2)*%pi/4, which is probably correct according to quad_qags. This latter integral works because intsc1 notices that the interval length is a rational multiple of %pi and breaks up the integral. However, for the former integral, intsc1 gives up because the interval length is not a multiple of %pi. Since we now have a floor function that works well, we should try to extend intsc1 to accept all numeric limits. This issue affects all integrals of trig functions that are handled by intsc1. See also the related bug 1552789. ---------------------------------------------------------------------- Comment By: Julien B. O. (jul059) Date: 2007-07-11 21:53 Message: Logged In: YES user_id=1610192 Originator: NO Just wanted to say that this bug is not present in maxima 5.10.0. In fact, it returns (sqrt(2)*atan(sqrt(2)*tan(8)))/2, which is correct. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1741705&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-1741705 ] integrate(1/(sin(x)^2+1), x, 0, 8) wrong From: SourceForge.net - 2007-07-29 16:25:09 ```Bugs item #1741705, was opened at 2007-06-22 11:59 Message generated for change (Comment added) made by dgildea You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1741705&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core - Integration Group: None >Status: Pending >Resolution: Fixed Priority: 5 Private: No Submitted By: Raymond Toy (rtoy) Assigned to: Nobody/Anonymous (nobody) Summary: integrate(1/(sin(x)^2+1),x,0,8) wrong Initial Comment: integrate(1/(sin(x)^2+1),x,0,8) returns sqrt(2)/2*atan(sqrt(2)*tan(8)) + %pi/sqrt(2) This is not right. But integrate(1/(sin(x)^2+1),x,0,5*%pi/2) returns 5*sqrt(2)*%pi/4, which is probably correct according to quad_qags. This latter integral works because intsc1 notices that the interval length is a rational multiple of %pi and breaks up the integral. However, for the former integral, intsc1 gives up because the interval length is not a multiple of %pi. Since we now have a floor function that works well, we should try to extend intsc1 to accept all numeric limits. This issue affects all integrals of trig functions that are handled by intsc1. See also the related bug 1552789. ---------------------------------------------------------------------- >Comment By: Dan Gildea (dgildea) Date: 2007-07-29 12:25 Message: Logged In: YES user_id=1797506 Originator: NO Fixed in cvs using pretty-good-floor-or-ceiling. (%i25) integrate(1/(sin(x)^2+1),x,0,8); (%o25) sqrt(2)*atan(sqrt(2)*sin(8)/cos(8))/2+sqrt(2)*%pi+%pi/sqrt(2) (Note: Expressions such as integrate(1/(sin(x-8)^2+1),x,0,8); still give the wrong answer.) ---------------------------------------------------------------------- Comment By: Julien B. O. (jul059) Date: 2007-07-11 21:53 Message: Logged In: YES user_id=1610192 Originator: NO Just wanted to say that this bug is not present in maxima 5.10.0. In fact, it returns (sqrt(2)*atan(sqrt(2)*tan(8)))/2, which is correct. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1741705&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-1741705 ] integrate(1/(sin(x)^2+1), x, 0, 8) wrong From: SourceForge.net - 2007-08-13 02:20:14 ```Bugs item #1741705, was opened at 2007-06-22 08:59 Message generated for change (Comment added) made by sf-robot You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1741705&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core - Integration Group: None >Status: Closed Resolution: Fixed Priority: 5 Private: No Submitted By: Raymond Toy (rtoy) Assigned to: Nobody/Anonymous (nobody) Summary: integrate(1/(sin(x)^2+1),x,0,8) wrong Initial Comment: integrate(1/(sin(x)^2+1),x,0,8) returns sqrt(2)/2*atan(sqrt(2)*tan(8)) + %pi/sqrt(2) This is not right. But integrate(1/(sin(x)^2+1),x,0,5*%pi/2) returns 5*sqrt(2)*%pi/4, which is probably correct according to quad_qags. This latter integral works because intsc1 notices that the interval length is a rational multiple of %pi and breaks up the integral. However, for the former integral, intsc1 gives up because the interval length is not a multiple of %pi. Since we now have a floor function that works well, we should try to extend intsc1 to accept all numeric limits. This issue affects all integrals of trig functions that are handled by intsc1. See also the related bug 1552789. ---------------------------------------------------------------------- >Comment By: SourceForge Robot (sf-robot) Date: 2007-08-12 19:20 Message: Logged In: YES user_id=1312539 Originator: NO This Tracker item was closed automatically by the system. It was previously set to a Pending status, and the original submitter did not respond within 14 days (the time period specified by the administrator of this Tracker). ---------------------------------------------------------------------- Comment By: Dan Gildea (dgildea) Date: 2007-07-29 09:25 Message: Logged In: YES user_id=1797506 Originator: NO Fixed in cvs using pretty-good-floor-or-ceiling. (%i25) integrate(1/(sin(x)^2+1),x,0,8); (%o25) sqrt(2)*atan(sqrt(2)*sin(8)/cos(8))/2+sqrt(2)*%pi+%pi/sqrt(2) (Note: Expressions such as integrate(1/(sin(x-8)^2+1),x,0,8); still give the wrong answer.) ---------------------------------------------------------------------- Comment By: Julien B. O. (jul059) Date: 2007-07-11 18:53 Message: Logged In: YES user_id=1610192 Originator: NO Just wanted to say that this bug is not present in maxima 5.10.0. In fact, it returns (sqrt(2)*atan(sqrt(2)*tan(8)))/2, which is correct. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1741705&group_id=4933 ```