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MathGroup Archive 2004

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Re: System of NonLinear Inequalities

  • To: mathgroup at smc.vnet.net
  • Subject: [mg48589] Re: [mg48511] System of NonLinear Inequalities
  • From: "maurizio lisciandra" <lisciandra at hotmail.com>
  • Date: Sat, 5 Jun 2004 19:58:09 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Thanks Andrzej,

I did wrote with the correct syntax when I put the system in Mathematica. I 
did find a solution though. I just run a loop with do and substitute for x, 
a, and F, and I found out that the solution is empty. At the beginning I 
thought that a Mathematica could do something like this, but then I realised 
that I was asking too much. I find this software extraordinary though. Thank 
you anyway for your answer.

Maurizio.



>From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
To: mathgroup at smc.vnet.net
>To: "maurizio lisciandra" <lisciandra at hotmail.com>
>CC: mathgroup at smc.vnet.net
>Subject: [mg48589] Re: [mg48511] System of NonLinear Inequalities
>Date: Fri, 4 Jun 2004 23:10:01 +0900
>
>First of all, your inequalities are not written using Mathematica syntax 
>(you can't use square brackets in this way). But looking at them I see it 
>does not matter whether you use proper syntax or not: no computer program 
>will ever solve a system of inequalites involving someting like x^(2/(2 - 
>x)). Your only chance is a human brain and some fantastic stroke of luck.
>Sorry for being so unhelpful.
>
>Andrzej
>
>On 4 Jun 2004, at 17:49, maurizio lisciandra wrote:
>
>>Dear Friends,
>>
>>I tried to solve the following system of nonlinear inequalities with
>>Mathematica 5.0:
>>
>>F < (1/2)*[a^(x/(2 - x))]*[x^(2/(2 - x))] &&
>>(2*a*B)^(x/2) + F - B > (2*a*F)^(x/2) &&
>>F > B > 0 &&
>>0 <= a <= 1 &&
>>0 < x < 2.
>>
>>I tried with Reduce, SolveInequality, SemiAlgebraicComponent, 
>>FindInstance,
>>but all these function do not solve it. I tried to substitute x for some
>>fixed value, but again I cannot solve it. The only value that I can
>>substitute for x is 1, and in this case the solution is an empty space. I
>>may be happy if I find a value that solves the system, although I really
>>need for which inetervals in the variable this system is not an empty 
>>space.
>>
>>Hope some nice Mathematica expert can help me.
>>
>>Cheers,
>>
>>Maurizio Lisciandra
>>Trinity College
>>Cambridge (UK)
>>
>>_________________________________________________________________
>>Ricerche online più semplici e veloci con MSN Toolbar!
>>http://toolbar.msn.it/
>>
>>
>

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