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 >