Re: series expansions in two variables problem
- To: mathgroup at smc.vnet.net
- Subject: [mg39523] Re: series expansions in two variables problem
- From: "Steve Luttrell" <luttrell at _removemefirst_westmal.demon.co.uk>
- Date: Fri, 21 Feb 2003 04:08:02 -0500 (EST)
- References: <b329vc$b2q$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Something like this might do the trick:
Expand[Normal[Series[1/((1 - \[Epsilon])*(1 - \[Sigma])), {\[Epsilon], 0,
1},
{\[Sigma], 0, 1}]]] /. \[Epsilon]*\[Sigma] -> 0
--
Steve Luttrell
West Malvern, UK
"Martin" <mc799 at ic.ac.uk> wrote in message news:b329vc$b2q$1 at smc.vnet.net...
> hi,
> I'm expanding an expression in two variables (sigma and epsilon, say),
> but am having trouble persuading Mathematica to chuck away terms of
> form epsilon*sigma.
>
> ie I'm getting
>
> A + B*sigma + C*epsilon + D*sigma*epsilon + O(sigma^2) + O(epsilon^2)
>
> and I'd like very much to lose the D terms.
>
> does anyone have any suggestions?
>
> Thanks
>
> Martin
>