Re: Coefficient in multivariate series

• To: mathgroup at smc.vnet.net
• Subject: [mg3611] Re: Coefficient in multivariate series
• From: pecora at zoltar.nrl.navy.mil (Louis M. Pecora)
• Date: Thu, 28 Mar 1996 00:10:24 -0500
• Organization: Naval Research Laboratory
• Sender: owner-wri-mathgroup at wolfram.com

```In article <4j7gsa\$af4 at dragonfly.wolfram.com>, Harald Berndt
<haraldb at nature.berkeley.edu> wrote:

> Samuel Bengmark wrote:
> >
> > I wonder if anyone out there knows how to get mathematica
> > to extract a coefficient of a monomial in a multivariate to
> > series or polynomial. For example how do I get mathematica to
> > give me the coefficient of x*y*z^3 in (1+x+y)^2*(2+y)*(5+z)^4.
>
>
> It's not very elegant, but I could'n get any simpler forms to work ...
> This will do it for you:
>
> First[
>         Select[t,
>         (MemberQ[#, x] && MemberQ[#, y] && MemberQ[#, Power[z, 3]])& ]
> ]

Hmmm...dumb question:

Why wouldn't

First[ Select[t, (MemberQ[#, x*y*z^2])& ] ]

work?  I'm probably missing something here.

--
Louis M. Pecora
pecora at zoltar.nrl.navy.mil

/* My views and opinions are not those of the U.S. Navy.
If you want those, you have to start a war.  */

==== [MESSAGE SEPARATOR] ====

```

• Prev by Date: Re: Combining ListPlotVectorField and ListDensityPlot
• Next by Date: Is there a quaternion package for Mma?
• Previous by thread: Re: Coefficient in multivariate series
• Next by thread: Re: Re: Coefficient in multivariate series