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Re: Factor, Extension

  • To: mathgroup at smc.vnet.net
  • Subject: [mg113778] Re: Factor, Extension
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Fri, 12 Nov 2010 05:27:16 -0500 (EST)

The _coefficients_ of your polynomial are 1 and 2, in the domain of 
integers.  Thus Sqrt[2] does _not_ appear in the polynomial. And so with 
Extension -> Automatic, there is no extension made.


On 11/11/2010 6:10 AM, 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
>

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
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Amherst, MA 01003-9305


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