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## [Maxima-bugs] [ maxima-Bugs-903190 ] sin(%pi+%pi*x) doesn't simplify

 [Maxima-bugs] [ maxima-Bugs-903190 ] sin(%pi+%pi*x) doesn't simplify From: SourceForge.net - 2004-02-24 03:25:57 ```Bugs item #903190, was opened at 2004-02-23 22:15 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=903190&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: sin(%pi+%pi*x) doesn't simplify Initial Comment: sin(%pi+%pi*x) doesn't simplify (cf 580721) ...similarly for other trig functions. The problem is that the %piargs code only looks for xxx+k*%pi/2 where xxx is %pi-free. Even sin(f(%pi)+%pi) doesn't simplify! There are two main ways to try to fix this: 1) *Add* a purely syntactic check before or after the existing semantic check. This is appealing because a) it will clearly work and b) it can't screw up the form of the expression. 2) Replace the current semantic check with one which looks for a k*%pi/2 term among other terms. For example, sin((%pi+1)^3) has a 12*%pi term, so could simplify to sin(%pi^3+6*%pi^2+8). But is that really useful? I don't think so, and if the user wanted it with the syntactic approach, s/he could just use expand. Even less useful would be sin((%pi+1)^3-12*%pi). So I think solution (1) is better, even if it seems inelegant to do two independent checks. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=903190&group_id=4933 ```

 [Maxima-bugs] [ maxima-Bugs-903190 ] sin(%pi+%pi*x) doesn't simplify From: SourceForge.net - 2004-02-24 03:25:57 ```Bugs item #903190, was opened at 2004-02-23 22:15 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=903190&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: sin(%pi+%pi*x) doesn't simplify Initial Comment: sin(%pi+%pi*x) doesn't simplify (cf 580721) ...similarly for other trig functions. The problem is that the %piargs code only looks for xxx+k*%pi/2 where xxx is %pi-free. Even sin(f(%pi)+%pi) doesn't simplify! There are two main ways to try to fix this: 1) *Add* a purely syntactic check before or after the existing semantic check. This is appealing because a) it will clearly work and b) it can't screw up the form of the expression. 2) Replace the current semantic check with one which looks for a k*%pi/2 term among other terms. For example, sin((%pi+1)^3) has a 12*%pi term, so could simplify to sin(%pi^3+6*%pi^2+8). But is that really useful? I don't think so, and if the user wanted it with the syntactic approach, s/he could just use expand. Even less useful would be sin((%pi+1)^3-12*%pi). So I think solution (1) is better, even if it seems inelegant to do two independent checks. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=903190&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-903190 ] sin(%pi+%pi*x) doesn't simplify From: SourceForge.net - 2006-07-24 02:13:53 ```Bugs item #903190, was opened at 2004-02-23 20:15 Message generated for change (Settings changed) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=903190&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: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: sin(%pi+%pi*x) doesn't simplify Initial Comment: sin(%pi+%pi*x) doesn't simplify (cf 580721) ...similarly for other trig functions. The problem is that the %piargs code only looks for xxx+k*%pi/2 where xxx is %pi-free. Even sin(f(%pi)+%pi) doesn't simplify! There are two main ways to try to fix this: 1) *Add* a purely syntactic check before or after the existing semantic check. This is appealing because a) it will clearly work and b) it can't screw up the form of the expression. 2) Replace the current semantic check with one which looks for a k*%pi/2 term among other terms. For example, sin((%pi+1)^3) has a 12*%pi term, so could simplify to sin(%pi^3+6*%pi^2+8). But is that really useful? I don't think so, and if the user wanted it with the syntactic approach, s/he could just use expand. Even less useful would be sin((%pi+1)^3-12*%pi). So I think solution (1) is better, even if it seems inelegant to do two independent checks. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=903190&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-903190 ] sin(%pi+%pi*x) doesn't simplify From: SourceForge.net - 2008-04-13 18:24:24 ```Bugs item #903190, was opened at 2004-02-23 22:15 Message generated for change (Comment added) made by dgildea You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=903190&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: None >Status: Closed >Resolution: Fixed Priority: 5 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: sin(%pi+%pi*x) doesn't simplify Initial Comment: sin(%pi+%pi*x) doesn't simplify (cf 580721) ...similarly for other trig functions. The problem is that the %piargs code only looks for xxx+k*%pi/2 where xxx is %pi-free. Even sin(f(%pi)+%pi) doesn't simplify! There are two main ways to try to fix this: 1) *Add* a purely syntactic check before or after the existing semantic check. This is appealing because a) it will clearly work and b) it can't screw up the form of the expression. 2) Replace the current semantic check with one which looks for a k*%pi/2 term among other terms. For example, sin((%pi+1)^3) has a 12*%pi term, so could simplify to sin(%pi^3+6*%pi^2+8). But is that really useful? I don't think so, and if the user wanted it with the syntactic approach, s/he could just use expand. Even less useful would be sin((%pi+1)^3-12*%pi). So I think solution (1) is better, even if it seems inelegant to do two independent checks. ---------------------------------------------------------------------- >Comment By: Dan Gildea (dgildea) Date: 2008-04-13 14:24 Message: Logged In: YES user_id=1797506 Originator: NO Fixed in trigi.lisp rev 1.30 (using solution 2 above, however). (%i32) sin(%pi+%pi*x); (%o32) -sin(%pi*x) (%i33) sin((%pi+1)^3); (%o33) -sin(%pi^3+3*%pi^2+1) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=903190&group_id=4933 ```