[Maxima-bugs] [ maxima-Bugs-3541292 ] error in residue calculation?

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Bugs item #3541292, was opened at 2012-07-07 19:22
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Category: Lisp Core - Integration
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: https://www.google.com/accounts ()
Assigned to: Nobody/Anonymous (nobody)
Summary: error in residue calculation?

Initial Comment:
Maxima 5.27.0 http://maxima.sourceforge.net
using Lisp SBCL 1.0.24
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1)  residue(( x/((4*x - 1)*(t^2 - t + x)) ),t,(1-sqrt(1-4*x))/2);
(%o1)                                  0

But apparently this should give a result in x?

sage: from sympy import Symbol, residue
sage:  x = Symbol("x")
sage:  t = Symbol("t")
sage: residue(x/((4*x - 1)*(t^2 - t + x)),t,(1-sqrt(1-4*x))/2)
-x/((-4*x + 1)**(1/2)*(4*x - 1))

This was first reported at http://ask.sagemath.org/question/1588/calculating-residue-with-maxima_methods

I make no claim for the mathematical correctness - just reporting quickly - but since the function has t in the denominator, that it would be nonzero seems reasonable.

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