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Re: Finding multiple roots - RootsInRange.nb (1/1)

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  • Subject: [mg39310] Re: Finding multiple roots - RootsInRange.nb (1/1)
  • From: Paul Abbott <paul at>
  • Date: Tue, 11 Feb 2003 04:40:50 -0500 (EST)
  • Organization: The University of Western Australia
  • References: <asn57g$488$>
  • Sender: owner-wri-mathgroup at

In article <asn57g$488$1 at>,
 "Novak Petrovic" <novak at> wrote:

> I'm trying to find roots of the characteristic equation of a
> dielectric-loaded waveguide. There are multiple roots of the equation and I
> use FindRoot to find them. The sequence of roots is very important in my
> further calculations.
> Is there a routine or a clever way to (numerically) find all the roots of an
> equation in a predefined values?
> As it is now I have to look for each individual root manually and it gets a
> bit tedious as the number of required modes increases.

I wrote a function called RootsInRange which does exactly what you want 
(attached). This originally appeared in The Mathematica Journal which is 
a good resource for such applications.

[contact the author to get the attachment - moderator]


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