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Re: Problem NSolve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg90658] Re: Problem NSolve
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Fri, 18 Jul 2008 04:01:21 -0400 (EDT)
  • Organization: Uni Leipzig
  • References: <g5n45f$sb8$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

"=" is Set[] and "==" is Equal[] you need *only* Equal[]
and never never *NEVER* Set[] in the definitions of
the equations, i.e.
ecu{lhs1==0,lhs2==0,...,lhs23}
                  ^
                  |

Regards
   Jens

Jorge wrote:
> Hello! To begin to ask for excuses you for my English poor level... I am a Spanish student of Chemical Engineering. Now I am employed at the simulation of a series of chemical reactions with Mathematica. 
> 
> As soon as I have programmed the problem to resolving, 23 equations with 23 variables, I use the function Nsolve, but the program returns to me the following message of mistake 
> 
> General::ivar: 0 is not a valid variable. >>
> 
> I have programmed my problem of the following form:
> 
> ecu{lhs1==0,lhs2=0,...,lhs23}
> sol=Nsolve[ecu{var1,var2,...,var23}]
> 
> 
> Might someone help?
> 
> Thank you very much! 
> Jorge
> 


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