Re: a fault in the Factor[] function for polynomials?
- To: mathgroup at smc.vnet.net
- Subject: [mg70414] Re: a fault in the Factor[] function for polynomials?
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Mon, 16 Oct 2006 02:34:00 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <egse02$cpp$1@smc.vnet.net>
Roger Bagula wrote:
> Expand[(x^4 + 2*Sqrt[3]x^2 - 1)(x^4 - 2*Sqrt[3]x^2 - 1)]
> 1 - 14x^4 + x^8
> Factor[%]
> (1 - 4x^2 + x^4)(1 + 4x^2 + x^4)
>
In[1]:=
expr1 = Expand[(x^4 + 2*Sqrt[3]*x^2 - 1)*
(x^4 - 2*Sqrt[3]*x^2 - 1)]
Out[1]=
4 8
1 - 14 x + x
In[2]:=
expr2 = Factor[expr1]
Out[2]=
2 4 2 4
(1 - 4 x + x ) (1 + 4 x + x )
In[3]:=
Simplify[expr1 == expr2]
Out[3]=
True