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] ====