From: SourceForge.net <no...@so...> - 2008-10-10 21:10:46
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Bugs item #2158174, was opened at 2008-10-10 17:10 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=2158174&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 - Limit Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: The Henman (rvh2007) Assigned to: Nobody/Anonymous (nobody) Summary: Bug in Limit of a function Initial Comment: Try (%i1) kill(all); (eq0) done (%i1) assume_pos:true; (eq1) true (%i2) (declare(n,integer),assume(sigma>0,equal(n-1, 0))); (eq2) [sigma>0,equal(n,1)] (%i3) f(x):=(sqrt(2)/(2*sqrt(%pi)*sqrt(sigma)))*exp(-(x^2/(2*sigma))); (eq3) f(x):=sqrt(2)/(2*sqrt(%pi)*sqrt(sigma))*exp(-x^2/(2*sigma)) (%i4) integrate(f(x),x,minf,inf); (eq4) 1 (%i5) integrate(x^2*f(x), x, minf, inf)-(integrate(x*f(x), x, minf, inf))^2; (eq5) sigma (%i6) integrate(x*f(a*x-b^2),x,minf,inf); (eq6) b^2/a^2 (%i7) limit(integrate((a*x^3+b*x^2+c*x+d)*f(x^n), x, minf, inf), sigma,0); (eq7) 0 (%i8) limit(integrate((a*x^3+b*x^2+c*x+d)*f(x), x, minf, inf), sigma,0); (eq8) d Output 7 is 0 and output 8 is d. They can't both be right since input 2 declares n=1, so they are equivilent. Rich Hennessy Maxima version: 5.16.3 Maxima build date: 22:48 8/24/2008 host type: i686-pc-mingw32 lisp-implementation-type: GNU Common Lisp (GCL) lisp-implementation-version: GCL 2.6.8 ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2158174&group_id=4933 |
From: SourceForge.net <no...@so...> - 2008-10-14 21:19:36
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Bugs item #2158174, was opened at 2008-10-10 17:10 Message generated for change (Comment added) made by dgildea You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2158174&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 - Limit Group: None >Status: Closed >Resolution: Fixed Priority: 5 Private: No Submitted By: The Henman (rvh2007) >Assigned to: Dan Gildea (dgildea) Summary: Bug in Limit of a function Initial Comment: Try (%i1) kill(all); (eq0) done (%i1) assume_pos:true; (eq1) true (%i2) (declare(n,integer),assume(sigma>0,equal(n-1, 0))); (eq2) [sigma>0,equal(n,1)] (%i3) f(x):=(sqrt(2)/(2*sqrt(%pi)*sqrt(sigma)))*exp(-(x^2/(2*sigma))); (eq3) f(x):=sqrt(2)/(2*sqrt(%pi)*sqrt(sigma))*exp(-x^2/(2*sigma)) (%i4) integrate(f(x),x,minf,inf); (eq4) 1 (%i5) integrate(x^2*f(x), x, minf, inf)-(integrate(x*f(x), x, minf, inf))^2; (eq5) sigma (%i6) integrate(x*f(a*x-b^2),x,minf,inf); (eq6) b^2/a^2 (%i7) limit(integrate((a*x^3+b*x^2+c*x+d)*f(x^n), x, minf, inf), sigma,0); (eq7) 0 (%i8) limit(integrate((a*x^3+b*x^2+c*x+d)*f(x), x, minf, inf), sigma,0); (eq8) d Output 7 is 0 and output 8 is d. They can't both be right since input 2 declares n=1, so they are equivilent. Rich Hennessy Maxima version: 5.16.3 Maxima build date: 22:48 8/24/2008 host type: i686-pc-mingw32 lisp-implementation-type: GNU Common Lisp (GCL) lisp-implementation-version: GCL 2.6.8 ---------------------------------------------------------------------- >Comment By: Dan Gildea (dgildea) Date: 2008-10-14 17:19 Message: Duplicate of [ 707253 ] limit(x^y,x,0) (y=0) => 0. Fixed in simp.lisp 1.58 and limit.lisp 1.56. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2158174&group_id=4933 |