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MathGroup Archive 2000

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Re: Solve...

  • To: mathgroup at smc.vnet.net
  • Subject: [mg25737] Re: [mg25681] Solve...
  • From: Richard Palmer <mapsinc at bellatlantic.net>
  • Date: Sat, 21 Oct 2000 14:42:48 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

I solved the system with the latest release on the MAC.  Nothing about an
illegal operation.  However I got NULLs in the answer.

A workaround might be to change the real #s in the function to exact numbers
and solve that.  It worked for me (4 long messy roots which were a function
of k).

Regards,

Richard Palmer



f[w_] := 1/(w^2)  + (9/30)/(w - 2 Sqrt[200/10]k)^2   -
    1 - (3/30)/( Sqrt[200/10]k^2 )

solutions = Solve[eqn, w];

InputForm [solutions/.k->1]

 {{w -> -0.9904772020959722 + 3.9504822155621816*^-15*I}, {w ->
      9.488938070874521 - 7.935033236408749*^-15*I}, {w ->
      0.9913059232704029 - 6.17519060357073*^-15*I}, {w ->
      8.398777027949366 + 1.0159741624417298*^-14*I}}



on 10/19/00 4:35 AM, Anesh Sooklal at anesh at fermi.udw.ac.za wrote:

> Dear mathgroup,
> 
> I have been trying to solve the following equation using Solve,
> When I type in the following line I get a message saying that an illegal
> operation has been performed.
> 
> f[w_]: = 1./(w^2)  + (.9/30.)/(w - 2. Sqrt[200./10.]k)^2   - 1.-
> (3./30.)/( Sqrt[200./10.]k^2 )
> 
> Solve[f[w]==0., w]
> 
> Can anyone tell me what I am doing wrong. My aim is to generate a set a
> roots,w , which is a function of k.
> 
> Thanking you in advance
> Aneshkumar Sooklal
> Research Assistant
> Dept. of Physics
> University of Durban-Westville
> South Africa
> 
> Tel: (031) 204 4991
> email: anesh at fermi.udw.ac.za
> 
> Physics Homepage: http://fermi.udw.ac.za
> Plasma Physics Homepage:  http://plasma.udw.ac.za
> 
> 
> 
> 



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