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Plotting implicit functions with multiple branches

  • To: mathgroup at smc.vnet.net
  • Subject: [mg42725] Plotting implicit functions with multiple branches
  • From: "Alan" <infoNOSPAM at optioncity.net>
  • Date: Wed, 23 Jul 2003 00:25:16 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

I have been spending some time assembling a plot of a function
y(x) where there are multiple branches to the function. My
specific example is where y(x) is defined implicitly as the solution
to the equation

   Sin[y]/y  = E^x / ( a - b x) ,  where a and b are positive constants.

For any solution y(x), there is also a solution -y(x), so suppose one just
wants to plot solutions y(x) for y >= 0.  As it turns out, for x greater
than
some values, there are an infinity of solutions which could be labeled
y(x,k), k = 1, 2 ...
For any range (xmin, xmax) and (0, ymax) there are only a finite number of
these solution or branches.
As x grows large, each branch approache the asymptote y = 2 k Pi from below.

My question is whether anyone knows of a general algorithm or package
to automate the generation of this type of plot, for say a general implicit
equation
of the form f(y) = g(x) where the equation has multiple solutions?
My current method is quite tedious: identifying branches, creating
individual plots, and using Show to combine them. I could live with that and
expect to
more fully automate this *particular* function. But I have some more
complicated functions
f(y) = g(x) that I would like to consider and would really like an automated
general method,
if such exists. Ideally, there would be something like a function

ImplicitPlot[ f[y] == g[x], Ranges, Options]

Thanks for any advice.


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