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Re: solve output "problem"

  • To: mathgroup at smc.vnet.net
  • Subject: [mg59066] Re: solve output "problem"
  • From: Peter Pein <petsie at dordos.net>
  • Date: Thu, 28 Jul 2005 02:26:12 -0400 (EDT)
  • References: <200507260801.EAA00224@smc.vnet.net> <dc76fj$jrc$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Pratik Desai schrieb:
> Selina wrote:
> 
> 
>>Dear all,
>>
>>I have a (possibly simple) problem interpreting the output of Solve. I am solving two nonlinear equations, and I get a list of several solutions, each of which are huge equations, which should be functions of my parameters. Anyway, I am not sure how to describe the problem but the output of Solve involves the following: #1, #1^2, .....,#1^6, along with everything else, and at the end there is an & symbol--something like "&, 2]" at the end of the second solution, "&, 6]" at the end of the 6th solution etc. What might be the reason why the output looks like this, and is there a way to convert this to a "normal" equation (without the #1's etc.)?
>>
>>Any help would be appreciated, thanks a lot in advance.
>>
>> 
>>
> 
> I suspect you have a functional output in terms of Root. Look at the 
> help on Root
> As far as I can understand, you can get a normal equation by
> First[expr][x]
> where x is your variable of interest. But that probably won't solve your 
> problem, just puts it back in the "normal" form.
> 
> ...
> Best regards
> Pratik
> 
Not really... First[Root[f,index]][x] evaluates to f[x] which brings you
back to "the root of your problem" ;-), which is f[x]==0. It does _not_
in any way 'normalize' the roots.

-- 
Peter Pein
Berlin


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