Re: Simplifying Ploynomials
- To: mathgroup at smc.vnet.net
- Subject: [mg5672] Re: Simplifying Ploynomials
- From: hanson at physics.auburn.edu (James D Hanson)
- Date: Tue, 7 Jan 1997 11:22:47 -0500
- Organization: Auburn University Physics
- Sender: owner-wri-mathgroup at wolfram.com
In article <5ap4ni$kv2 at dragonfly.wolfram.com>,
Ersek_Ted%PAX1A at mr.nawcad.navy.mil wrote:
> Dear Math Group,
>
> The two polynomials "messy" and "clean" below are equivalentl.
>
> messy = c0 + a*c1 - b*c1 + a^2*c2 - 2*a*b*c2 + b^2*c2
>
> clean = c0 + c1(a-b) + c2(a-b)^2
>
> If I get a polynomial like the messy one, how can I get Mma
> to convert is to the clean polynimial.
>
> I don't yet have Version 3..0.
> Using Collect and Factor in version 2.2 does no good.
> Maybe FullSimplify in version 3.0 will work.
>
> Still I would like to do this without using FullSimplify,
> because it can take a very long time.
>
> Please Help
> T.E.
It is not very elegant, but it works.
In[1]:=
messy = c0 + a*c1 - b*c1 + a^2*c2 - 2*a*b*c2 + b^2*c2
Out[1]=
2 2
c0 + a c1 - b c1 + a c2 - 2 a b c2 + b c2
In[2]:=
clean = Expand[messy /. a -> x + b] /. x -> a - b
Out[2]=
2
c0 + (a - b) c1 + (a - b) c2
--
James D. Hanson ph. (334) 844-5044
Department of Physics fax (334) 844-4613
206 Allison Laboratory
Auburn University, AL 36849-5311 hanson at physics.auburn.edu