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Re: BesselJZeros problem/bug?

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  • Subject: [mg17047] Re: BesselJZeros problem/bug?
  • From: Alan Lewis <alanlewis at>
  • Date: Wed, 14 Apr 1999 02:11:58 -0400
  • Organization: @Home Network
  • References: <7es1a3$>
  • Sender: owner-wri-mathgroup at

Fails on my machine too. From the large argument asymptotic formula,
try a plot of [Sqrt[2/(Pi x)] Cos[x - Pi/4] vs J0[x]. They are
very close and so the zeros are very close to (n-1/4)Pi,  n=1,2,...
So, FindRoot will do it:

Table[ x/.FindRoot[BesselJ[0,x]==0,{x,(n-1/4)Pi}],{n,1,nmax}]


Tim Birks wrote:
> I have a very simple notebook with just the following two cells:
> << NumericalMath`BesselZeros`
> BesselJZeros[0,{3,3}]
> Having run the first cell to load the add-on package, running the second
> cell is supposed to return a list containing the value of the 3rd zero
> of the Bessel function J0. However, for me it just never returns at all.
> Is this a bug? and is there a work-around?
> There are no problems finding the 1st and 2nd zeros of J0, nor any of
> the zeros of J1, J2, etc. I am running Mathematica on a PC with
> Windows 95.
> Any ideas?
> T.

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