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Re: Factor, Extension

• To: mathgroup at smc.vnet.net
• Subject: [mg113777] Re: Factor, Extension
• From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
• Date: Fri, 12 Nov 2010 05:27:05 -0500 (EST)

On 11 Nov 2010, at 12:10, janos wrote:

> Dear All,
> 
> What is the meaning of the help of Factor:
> 
> Factor[poly,Extension->Automatic] will extend the domain of
> coefficients to include any algebraic numbers that appear in poly.  =BB
> 
> if
> 
> Factor[x^2 - 2, Extension -> Automatic]
> 
> does not seem to work in the same way as
> 
> Factor[x^2 - 2, Extension -> Sqrt[2]]
> 
> Thanks,
> 
> J=E1nos
> 

Factor[x^2 - 2 Sqrt[2] x + 2]

x^2-2 Sqrt[2] x+2

Factor[x^2 - 2 Sqrt[2] x + 2, Extension -> Automatic]

(Sqrt[2]-x)^2

Andrzej Kozlowski