Re: positive root only using Solve[]
- To: mathgroup at smc.vnet.net
- Subject: [mg41815] Re: [mg41791] positive root only using Solve[]
- From: Bobby Treat <drmajorbob-MathGroup3528 at mailblocks.com>
- Date: Fri, 6 Jun 2003 09:50:46 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Solve[x^2 == 1, x] Cases[%, Rule[a_, b_?Positive] :> Rule[a, b], 2] or Solve[x^2 == 1, x] x /. % Select[%, Positive] Bobby -----Original Message----- From: seferiad <seferiad at pacbell.net> To: mathgroup at smc.vnet.net Subject: [mg41815] [mg41791] positive root only using Solve[] 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