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MathGroup Archive 2005

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Re: Bug in Reduce?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg60432] Re: [mg60406] Bug in Reduce?
  • From: Chris Chiasson <chris.chiasson at gmail.com>
  • Date: Fri, 16 Sep 2005 03:49:23 -0400 (EDT)
  • References: <dfrhi4$g4l$1@smc.vnet.net> <dg8lfv$r8g$1@smc.vnet.net> <200509140926.FAA01590@smc.vnet.net> <200509150916.FAA15875@smc.vnet.net>
  • Reply-to: chris.chiasson at gmail.com
  • Sender: owner-wri-mathgroup at wolfram.com

On Mathematica 5.2 on Windows, this calculation returns:
(a == 0 && b == 0) || (c == 0 && d == 0)

On 9/15/05, Kennedy <jack at realmode.com> wrote:
> The source of this apparent bug could be my misunderstanding of the middle,
> "vars" parameter of Reduce, but it sure seems like the following output
> indicates that  c  must be  0  for my two equations to be satisfied, when in
> fact if  a  and  b  are both  0,  c  does not need to be  0.
> 
> Regards,
> Jack
> 
> In[1]:=
> Reduce[{a c - b d == 0, a d + b c == 0}, {a, b, c, d}, Reals] //
> FullSimplify
> 
> Out[1]=
> c == 0 && (d == 0 || (a == 0 && b == 0))
> 
> (version 5.1 for Windows)
> 
> 


-- 
Chris Chiasson
http://chrischiasson.com/
1 (810) 265-3161


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