Re: Solving inequation

*To*: mathgroup at smc.vnet.net*Subject*: [mg2084] Re: Solving inequation*From*: Christian.Jost at epc.u-psud.fr (Christian Jost)*Date*: Fri, 29 Sep 1995 01:13:07 -0400*Organization*: Universite Paris-Sud XI

In article <DFCG6A.Lz6 at wri.com>, uthaisom at veena.cps.msu.edu (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 psisun.u-psud.fr