Re: Is this possible? Residue computation leads to complexInfinity?
- To: mathgroup at smc.vnet.net
- Subject: [mg60735] Re: Is this possible? Residue computation leads to complexInfinity?
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Mon, 26 Sep 2005 04:05:40 -0400 (EDT)
- Organization: The Open University, Milton Keynes, U.K.
- References: <dh5hl9$dlc$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
kiki wrote:
> In[15]:=
> \!\(FullSimplify[Residue[\(\[ImaginaryI]\ z\)\/\(1 - \((2 + 4\ a)\)\ z\^2 +
> z\
> \^4\), \@\(a + 1\) - \@a], \ a > 0]\)
>
> Out[15]=
> \!\(Residue[ComplexInfinity, \(-\@a\) + \@\(1 + a\)]\)
>
>
The syntax is not correct. Try
In[1]:=
FullSimplify[Residue[(I*z)/(1 - (2 + 4*a)*z^2 + z^4),
{z, Sqrt[a + 1] - Sqrt[a]}], a > 0]
Out[1]=
(I*(-1 + Sqrt[1 + 1/a]))/(8*(-1 - a + Sqrt[a + a^2]))
Regards,
/J.M.