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Re: problem with DSolve and spheroidal harmonics

  • To: mathgroup at smc.vnet.net
  • Subject: [mg128313] Re: problem with DSolve and spheroidal harmonics
  • From: Tom Dickens <tomdickens at att.net>
  • Date: Sat, 6 Oct 2012 01:50:52 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
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  • References: <k4lvck$d2q$1@smc.vnet.net>

Thanks to Bob Hanlon who pointed out my misprint: I had " m^2 - "
instead of the correct "m^2 / " .

THis happened because I have a homebrew code that I use to modify
clipboard contents so I can use them for file names, and it changed
the "/" to "-".

Tom

On Fri, 5 Oct 2012 06:40:20 +0000 (UTC), Tom Dickens
<tomdickens at att.net> wrote:

>All,
>
>I wonder if this is a bug. I'm working on a project involving
>spheroidal harmonics, and tried the following example from the Help:
>
>DSolve[(1 - x^2) y''[x] -  2 x y'[x] + (SpheroidalEigenvalue[n, m, c]
>+ c^2 (1 - x^2) - m^2-(  1 - x^2)) y[x] == 0, y, x]
>
> {{y -> Function[{x},  C[1] SpheroidalPS[n, m, c, x] + C[2]
>SpheroidalQS[n, m, c, x]]}}
>
>This shows (in the Help) that the defining differential equation is
>solved correctly. However, when I run it in either v7 or v8 I get a
>differential root object
>
>{{y->DifferentialRoot[Function[{-[FormalY],-[FormalX]},{-[FormalY][-[FormalX]]
>(1--[FormalX]^2-c^2+-[FormalX]^2
>c^2+m^2-SpheroidalEigenvalue[n,m,c])+2 -[FormalX]
>(-[FormalY]^-[Prime])[-[FormalX]]+(-1+-[FormalX]^2)
>(-[FormalY]^-[Prime]-[Prime])[-[FormalX]]==0,-[FormalY][0]==C[1],(-[FormalY]^-[Prime])[0]==C[2]}]]}}
>
>Any thoughts?
>
>Thanks,
>Tom



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