Re: Incorrect result for improper integral with MMA?
- To: mathgroup at smc.vnet.net
- Subject: [mg8820] Re: Incorrect result for improper integral with MMA?
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Fri, 26 Sep 1997 00:33:43 -0400
- Organization: University of Western Australia
- Sender: owner-wri-mathgroup at wolfram.com
Chris Barker wrote:
> The command:
>
> Integrate[1/(x*Log[x]^2),{x,3,Infinity}]
>
> yields the result:
>
> \!\(\*
> RowBox[{
> \(Integrate::"idiv"\), \( : \ \),
> "\<"Integral of \!\(1\/\(x\\ \(Log[x]\)\^2\)\) does not converge on \
> \!\({3, \*InterpretationBox[\"\\[Infinity]\", DirectedInfinity[1]]}\)."\>"}]\)
>
> i.e. the integral does not converge. However, analytic techniques seem
> to indicate that the integral does indeed converge to 1/ln(3). Mimicing
> the analytic procedures step by step with mma also yields 1/ln(3). Am I
> being stupid, or is mma wrong?
Mathematica easily computes the indefinite integral -- from this you
will see why the integral does not converge on [3,Infinity).
Cheers,
Paul
____________________________________________________________________
Paul Abbott Phone: +61-8-9380-2734
Department of Physics Fax: +61-8-9380-1014
The University of Western Australia
Nedlands WA 6907 mailto:paul at physics.uwa.edu.au
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God IS a weakly left-handed dice player
____________________________________________________________________