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[Maxima-bugs] [ maxima-Bugs-727542 ] powerseries wrong
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From: SourceForge.net <no...@so...> - 2003-04-25 15:35:19
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Bugs item #727542, was opened at 2003-04-25 15:35 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=727542&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Martin Rubey (kratt5) Assigned to: Nobody/Anonymous (nobody) Summary: powerseries wrong Initial Comment: (C51) gf:-2*(175-1144*x-4882*x^3+4324*x^4-2072*x^5+416*x^6+3189*x^2)/ (2*x-1)^3/(4*x-1)/(x-1)^3$ (C52) taylor(gf,x,0,3); 2 3 (D52)/T/ 350 + 2262 x + 11634 x + 53650 x + . . . (C53) taylor(powerseries(gf,x,0),x,0,3); 2 3 (D53)/T/ 470 + 2862 x + 13524 x + 58750 x + . . . maybe this is related to sum(x^i,i,0,inf),x:0 giving 0, but I don't know... I checked D53 with Maple, so it seems that powerseries is wrong, not taylor. I converted the result of powerseries to the rational function again, and obtained: -2*(940-7436*x-41588*x^3-22066*x^5+40253*x^4+416*x^8-1816*x^7+7076*x^6+24227*x^2) /(2*x-1)^3/(4*x-1)/(x-2)^2/(x-1)^3 The difference between the two is 160*'SUM((I+1)*2^I*x^I,I,0,INF)-160*'SUM((I+1)*2^(-I-2)*x^I,I,0,INF) so the reason might be a simple typo (- instead of + or the like)... Should be possible to correct this... Martin ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=727542&group_id=4933 |