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Re: Real Solutions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg95809] Re: [mg95782] Real Solutions
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Wed, 28 Jan 2009 06:27:19 -0500 (EST)
  • Reply-to: hanlonr at cox.net

Select[Solve[x^3 - 2 x + 7 == 0, x], FreeQ[x /. #, Complex] &]

{{x -> 
       -(2*(2/(3*(63 - Sqrt[3873])))^
                (1/3)) - 
         ((1/2)*(63 - Sqrt[3873]))^
             (1/3)/3^(2/3)}}

Select[NSolve[x^3 - 2 x + 7 == 0, x], FreeQ[x /. #, Complex] &]

{{x->-2.25826}}


Bob Hanlon

---- =?UTF-8?B?S293YWxjenlrLVNjaHLDtmRlcg==?= at smc.vnet.net wrote: 

=============
Hi,
I need only the real solutions from Solve or NSolve. I found a 
complicated way with a lot of "ifs" to get, what I want. Is there an 
easier way to do this? (I don't want to use Reduce.)
Regards
J.Schroeder




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