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MathGroup Archive 2004

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Re: NSolve freezes on two polynomial equations

  • To: mathgroup at smc.vnet.net
  • Subject: [mg48430] Re: [mg48332] NSolve freezes on two polynomial equations
  • From: Daohua Song <ds2081 at columbia.edu>
  • Date: Sat, 29 May 2004 03:06:52 -0400 (EDT)
  • References: <200405251116.HAA03554@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

HI, Carlos,
     Try not to express like f[x,y]/g[x,y]==c, but f[x,y]=c g[x,y]; you
will get the answer
     {{xr-4.7561-12.5247 ,yr0.249478 -12.5247 },{xr-4.647-12.5247
,yr-0.804469-12.5247 },{xr0.072901 -12.5502 ,yr-0.284831-12.771},
{xr0.072901 -12.4992 ,yr-0.284831-12.2784 }}

Daohua
  On Tue, 25 May 2004,
Carlos Felippa wrote:

> This innocent looking system of 2 quadratic equations (extracted with
> InputForm from the guts of a large code) freezes Mathematica 4.2 on my
> Mac.  Same if NSolve is replaced by Solve. I wonder why, and how to
> fix it.  Thanks.
>
> ClearAll[x,y];
> eqs=
> {(37.5*(-0.005707305713190276 + 12.52471957392599*I +
>              x)*(4.672373972379857 + 12.52471957392599*I +
>              x))/((100. + 939.3539680444492*I)*x +
>          37.5*x^2 - 487.5*(0.4594268481272286 + 8.967155112255348*I +
>                y)*(1.1815987928984124 + 16.08228403559663*I +
>                y)) == -0.03653043382891893,
> (-487.5*(-1.0444224854481148 + 12.524719573925989*I +
>              y)*(0.6854481264737559 + 12.524719573925989*I +
>              y))/((100. + 939.3539680444492*I)*x +
>          37.5*x^2 - 487.5*(0.4594268481272286 + 8.967155112255348*I +
>                y)*(1.1815987928984124 + 16.08228403559663*I +
>                y)) == -0.8852848076704578};
> sol=NSolve[eqs,{x,y}]; Print[sol];
>


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