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Re: Simplify and Gather Terms in a Polynomial

• To: mathgroup at smc.vnet.net
• Subject: [mg46443] Re: Simplify and Gather Terms in a Polynomial
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Thu, 19 Feb 2004 03:01:50 -0500 (EST)
• Organization: Universitaet Leipzig
• References: <c0uu2k$e74$1@smc.vnet.net>
• Reply-to: kuska at informatik.uni-leipzig.de
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

Collect[] would do that for a polynomials. But your
form x *(y+y*x) is not in the classic form of a polynomial
in x and you must do that by hand

Expand[y(x + x^2)] /. x^n_.*a_. + x_^m_.*b_. :> x*(x^(n - 1)*a + x^(m -
1)*b)

Regards
  Jens

sabbri wrote:
> 
> I have two equivalent polynomial expressions. In the second, which
> should derive from the first, terms are gathered respecting to a
> particular variable. for example:
>  y(x+ x^2)
> I want to make it gathered for x
> x(y+yx)
> How can I give this command?