From: SourceForge.net <no...@so...> - 2006-12-22 20:03:33
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Bugs item #1370433, was opened at 2005-11-30 17:38 Message generated for change (Comment added) made by rtoy You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1370433&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 - Trigonometry Group: Fix for 5.9.2 >Status: Closed >Resolution: Fixed Priority: 5 Private: No Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: trigsimp(sqrt(%i2)) != sqrt(trigsimp(%i2)) Initial Comment: -------------------------------------------------- Maxima version: 5.9.2 Maxima build date: 9:5 10/12/2005 host type: i686-pc-mingw32 lisp-implementation-type: GNU Common Lisp (GCL) lisp-implementation-version: GCL 2.6.7 -------------------------------------------------- ################################################## # Start problem with sqrt and trigsimp: # # # # (%i2) 2*(cos(x)^2-sin(x)^2)+2; # # 2 2 # # (%o2) 2 (cos (x) - sin (x)) + 2 # # (%i3) trigsimp(sqrt(%i2)); # # (%o3) - 2 abs(cos(x)) # # (%i4) sqrt(trigsimp(%i2)); # # (%o4) 2 abs(cos(x)) # # # # End problem with sqrt and trigsimp. # ################################################## ---------------------------------------------------------------------- >Comment By: Raymond Toy (rtoy) Date: 2006-12-22 15:03 Message: Logged In: YES user_id=28849 Originator: NO Fixed by replacing call to radcan with ratsimp. ---------------------------------------------------------------------- Comment By: Raymond Toy (rtoy) Date: 2006-11-09 12:32 Message: Logged In: YES user_id=28849 This bug is caused by the call to radcan in trigsimp (share/trigonometry/trgsmp.mac). For the case trigsimp(sqrt(%i2)), radcan converts sqrt(2*(cos(x)^2-sin(x)^2)+2) int sqrt(2)*%i*sqrt(sin(x)^2-cos(x)^2-1). I don't think this is what we want. Perhaps replacing radcan with ratsimp would be better. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1370433&group_id=4933 |