Re: positive root only using Solve[]
- To: mathgroup at smc.vnet.net
- Subject: [mg41812] Re: [mg41791] positive root only using Solve[]
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Fri, 6 Jun 2003 09:50:42 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
You can use Select or Cases to select the positive solution fro the output returned by Solve. Or you can use InequalitySolve from the package Algebra`InequalitySolve or Experimental`CylindricalAlgebraicDecomposition to get: Experimental`CylindricalAlgebraicDecomposition[x^2==1&&x>0,x] x==1 Andrzej Kozlowski Yokohama, Japan http://www.mimuw.edu.pl/~akoz/ http://platon.c.u-tokyo.ac.jp/andrzej/ On Thursday, June 5, 2003, at 08:31 pm, seferiad wrote: > Hello, > Consider the following equation. > > Solve[x^2 ==1, x] > > Mathematica will output 1 and -1 for x. However, I only want > Mathematica to > output the positive solution (i.e., x -> 1), so I can use this > conveniently > in a subsequent equation. Is there a way to force the output to > produce only > the positive solution? Thanks, Jay > > >