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Re: Solving inequation

  • To: mathgroup at
  • Subject: [mg2084] Re: Solving inequation
  • From: Christian.Jost at (Christian Jost)
  • Date: Fri, 29 Sep 1995 01:13:07 -0400
  • Organization: Universite Paris-Sud XI

In article <DFCG6A.Lz6 at>, uthaisom at (Patchrawat
Uthaisombut) wrote:

> Hi,
> I am a new Mathematica user.
> I wonder if Mathematica can solve inequation.
> Something like
>         Solve[ k+s < s+1, k]
> If there is no such build-in function,
> suggestion to implement this is also appreciated.
To my knowledge, there is none, and with good reasons: when solving
inequalities each time you multiplicate or divide you have to know the
sign of the factor in order to keep the direction of the inequality
correct. In general mathematica hasn't this kind of information (I tried
once providing this information by setting the attribute to a variable
that its sign is positive, but mathematica oculd not use this
information), and when you are doing hand calculations you start
distinguishing cases. Maybe mathematica could do this, but in general
solving inequalities is much less straightforward than solving equalities

Hope that sounds reasonable, Christian.

Christian Jost, Universit=E9 Paris-Sud XI, Orsay, France
jost at

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