## [Maxima-bugs] [ maxima-Bugs-932302 ] partfrac of taylor bogus taychk2rat/FIX

 [Maxima-bugs] [ maxima-Bugs-932302 ] partfrac of taylor bogus taychk2rat/FIX From: SourceForge.net - 2004-04-09 13:45:22 ```Bugs item #932302, was opened at 2004-04-09 09:45 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=932302&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: partfrac of taylor bogus taychk2rat/FIX Initial Comment: expr: 1/(x^2-1)\$ texpr: taylor(expr,x,1,1)\$ ptexpr: partfrac(texpr,x) => (x+4/(x-1)-3)/8 NO! This is algebraically correct, but not in partfrac form. The correct answer is given by: partfrac(ratdisrep(texpr),x) == partfrac(ptexpr,x) => 1/(2*(x-1))+(x-3)/8 The immediate fix is to replace (DESETQ (RATFORM . EXP) (TAYCHK2RAT EXP)) with (DESETQ (RATFORM . EXP) (RATF (TAYCHK2RAT EXP))) however, I wonder if TAYCHK2RAT shouldn't be doing this. Compare: ratnumer(taylor(x+1/x,x,0,1)) => x+1/x ??? ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=932302&group_id=4933 ```

 [Maxima-bugs] [ maxima-Bugs-932302 ] partfrac of taylor bogus taychk2rat/FIX From: SourceForge.net - 2004-04-09 13:45:22 ```Bugs item #932302, was opened at 2004-04-09 09:45 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=932302&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: partfrac of taylor bogus taychk2rat/FIX Initial Comment: expr: 1/(x^2-1)\$ texpr: taylor(expr,x,1,1)\$ ptexpr: partfrac(texpr,x) => (x+4/(x-1)-3)/8 NO! This is algebraically correct, but not in partfrac form. The correct answer is given by: partfrac(ratdisrep(texpr),x) == partfrac(ptexpr,x) => 1/(2*(x-1))+(x-3)/8 The immediate fix is to replace (DESETQ (RATFORM . EXP) (TAYCHK2RAT EXP)) with (DESETQ (RATFORM . EXP) (RATF (TAYCHK2RAT EXP))) however, I wonder if TAYCHK2RAT shouldn't be doing this. Compare: ratnumer(taylor(x+1/x,x,0,1)) => x+1/x ??? ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=932302&group_id=4933 ```