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Re: Mathematica help (plotting solutions of transendental equation from

  • To: mathgroup at smc.vnet.net
  • Subject: [mg110032] Re: Mathematica help (plotting solutions of transendental equation from
  • From: "David Park" <djmpark at comcast.net>
  • Date: Sun, 30 May 2010 06:46:54 -0400 (EDT)

Something like this?

f[c_?NumericQ, m_?NumericQ, n_?NumericQ] := 
 FindRoot[{a - b == 2 \[Pi] (m - n) + ArcTan[(a - b)/c], 
   a + b == 2 \[Pi] (m + n)}, {{a, 2 I + 1}, {b, -2 I + 1}}] 

fParametrization[c_] := Chop[{a, b} /. f[c, 2, 3]]; 
ParametricPlot[fParametrization[c], {c, 0, 5}] 


David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/  



From: JustanotherDave [mailto:david.holdaway at gmail.com] 

I'm having trouble getting Mathematica to plot what I would like from
a system of equations. I have the function

f[c_?NumericQ, m_?NumericQ, n_?NumericQ] :=
 FindRoot[{a - b == 2*Pi*(m - n) + ArcTan[(a - b)/c],
   a + b == 2*Pi*(m + n)}, {{a, 2 I + 1}, {b, -2 I + 1}}]

Which evaluates to something like {a -> 13.333 + 2.99972*10^-20 I, b -
> -13.333 - 2.99972*10^-20 I}
What I would like is to be able to plot the imaginary values of a and
b on the same graph (varying the parameter c, keeping m and n
constant) but I'm not sure how to convert the FindRoot output to
plotable values




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