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MathGroup Archive 2001

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Re: How to save time with InequalitySolve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg30326] Re: [mg30305] How to save time with InequalitySolve
  • From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
  • Date: Sat, 11 Aug 2001 03:39:48 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Probably you can't. When your inequalities contain more than one 
variable and expressions which are neither polynomials nor rational 
functions you should consider yourself lucky if you ever obtain an 
explicit solution. The same by the way applies to equations. (This is 
not a computer algebra problem but a mathematical one).

Andrzej Kozlowski
Toyama International University
JAPAN
http://platon.c.u-tokyo.ac.jp/andrzej/

On Wednesday, August 8, 2001, at 02:33  PM, Nathan ZYLBERSZTEJN wrote:

> Hi,
>
> I want Mathematica to solve this system of inequalities. When I try
> the following expressions, Mathematica is gone for hours and never
> stops. How can I solve my system in a reasonable time?
>
>
> InequalitySolve[
>   -((-8*c*(-1 + d) + Sqrt[2 - 2*d]*
>          Sqrt[-4*c^2*(-2 + 5*d) + 3*d*(2 - 3*d + d^2)])*
>        (-4*c^2*(2 + d) + 3*d*(2 - 3*d + d^2) +
>         2*c*Sqrt[2 - 2*d]*Sqrt[-4*c^2*(-2 + 5*d) +
>            3*d*(2 - 3*d + d^2)]))/(54*c*(-2 + d)^2*d*
>       (-1 + 2*c + d)) > (4*Sqrt[2/3])/3 && 1 > c > 0 &&
>    1 > d > 0, {d, c}]
>
> Thanks a lot
>
> Nathan ZYLBERSZTEJN
>
>



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