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Re: Troubles with Integrating certain functions in 5.0

  • To: mathgroup at smc.vnet.net
  • Subject: [mg49136] Re: Troubles with Integrating certain functions in 5.0
  • From: Paul Abbott <paul at physics.uwa.edu.au>
  • Date: Fri, 2 Jul 2004 02:01:53 -0400 (EDT)
  • Organization: The University of Western Australia
  • References: <cc0n0q$kvs$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

In article <cc0n0q$kvs$1 at smc.vnet.net>,
 mdh at media.mit.edu (Matt Hancher) wrote:

> I'm running 5.0.0.0 on OS X, and Integrate is misbehaving.  Below I show 
> the results of performing the same definite integral two times.  The only 
> difference is that I pulled out the constant factor Sqrt[E] in the second 
> case.  Only the second case is correct; the Struve function shouldn't be 
> there in the first case.
> 
> I'm pretty sure I'm not just being dumb.  Anybody have any thoughts?
> I'd be curious to know how this plays out with other versions and on 
> other platforms....

I recently encountered the same bug and reported it to WRI. You get the 
same error with

  Integrate[Exp[a Cos[t]], {t,0,Pi}]/Pi

(the Struve function should not be there) and also with

  Table[Integrate[Exp[a Cos[t]] Cos[n t],{t,0,Pi}]/Pi, {n,3}]

where, in addition, the 0's are clearly incorrect.

Cheers,
Paul

> 
> In: Integrate[Exp[-Sin[x]^2]*Sqrt[E], {x, 0, Pi}]
> Out: Pi ( BesselI[0, 1/2] - StruveL[0, 1/2] )
> 
> Versus:
> 
> In: Integrate[Exp[-Sin[x]^2], {x, 0, Pi}]*Sqrt[E]
> Out: Pi BesselI[0,1/2]
> 
> Thanks for any thoughts,
> Matt
> 
> Matt Hancher
> NASA Ames Research Center
> Official: mdh at email.arc.nasa.gov
> Personal: mdh at media.mit.edu
>

-- 
Paul Abbott                                   Phone: +61 8 9380 2734
School of Physics, M013                         Fax: +61 8 9380 1014
The University of Western Australia      (CRICOS Provider No 00126G)         
35 Stirling Highway
Crawley WA 6009                      mailto:paul at physics.uwa.edu.au 
AUSTRALIA                            http://physics.uwa.edu.au/~paul


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