From: SourceForge.net <no...@so...> - 2008-02-22 14:16:41
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Bugs item #1899352, was opened at 2008-02-22 00:47 Message generated for change (Comment added) made by rtoy You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1899352&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 - Assume Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Alex Ghitza (aghitza) Assigned to: Nobody/Anonymous (nobody) Summary: integrate asks about (y-1)(y+1) after assume(y^2>1) Initial Comment: Here is the problematic session: Maxima 5.13.0 http://maxima.sourceforge.net Using Lisp CLISP 2.41 (2006-10-13) Distributed under the GNU Public License. See the file COPYING. Dedicated to the memory of William Schelter. This is a development version of Maxima. The function bug_report() provides bug reporting information. (%i1) assume(y^2>1); 2 (%o1) [y > 1] (%i2) integrate(log(x^2+y^2),x,0.0001414,1.); `rat' replaced 0.9998586 by 7071/7072 = .9998585972850679 `rat' replaced 1.414E-4 by 81/572843 = 1.413999996508642E-4 `rat' replaced 0.9998586 by 7071/7072 = .9998585972850679 `rat' replaced 0.9998586 by 7071/7072 = .9998585972850679 `rat' replaced 1.414E-4 by 81/572843 = 1.413999996508642E-4 `rat' replaced 0.9998586 by 7071/7072 = .9998585972850679 `rat' replaced 0.9998586 by 7071/7072 = .9998585972850679 `rat' replaced 1.414E-4 by 81/572843 = 1.413999996508642E-4 `rat' replaced 0.9998586 by 7071/7072 = .9998585972850679 Is (y - 1) (y + 1) positive, negative, or zero? positive; 2 2 Is y + x + 2 x + 1 positive or negative? positive; 2 2 1 (%o2) - 1.414E-4 log(1.0 y + 1.999396E-8) + log(y + 1) + 2 atan(-) y y 1.414E-4 - 2.0 atan(--------) y - 1.9997172 y (%i3) ---------------------------------------------------------------------- >Comment By: Raymond Toy (rtoy) Date: 2008-02-22 09:16 Message: Logged In: YES user_id=28849 Originator: NO Note that is((y-1)*(y+1)>0) returns unknown. If you say assume(y>1), integrate doesn't ask about that anymore. But it still asks about y^2+x^2+2*x+1. It should know that x > 0 and y > 0 here. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1899352&group_id=4933 |