From: SourceForge.net <noreply@so...>  20070729 16:25:09

Bugs item #1741705, was opened at 20070622 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: 20070729 12:25 Message: Logged In: YES user_id=1797506 Originator: NO Fixed in cvs using prettygoodfloororceiling. (%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(x8)^2+1),x,0,8); still give the wrong answer.)  Comment By: Julien B. O. (jul059) Date: 20070711 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 