Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2003
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2003

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Something wrong with this integral (see text)

  • To: mathgroup at smc.vnet.net
  • Subject: [mg44436] Re: Something wrong with this integral (see text)
  • From: "David W. Cantrell" <DWCantrell at sigmaxi.org>
  • Date: Sun, 9 Nov 2003 06:01:24 -0500 (EST)
  • References: <boif3m$oaf$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

"Ihor Stealth" <stealth at gmx.net> wrote:
> I calculated two expressions:
>
> FullSimplify[Integrate[(-L^2)/(L^2 + 1)*Cos[L], {L,0, Infinity}]]
>
> and
>
> FullSimplify[Integrate[(-1)/(L^2 + 1)*Cos[L], {L,0, Infinity}]]
>
> They gave the same result, but in the first expression when we take
> L->Infinity, it's impossible to take integral, but MAthematica CAN do
> that.
>
> What the explanation of this?

This question was posted, separately, by Ihor to sci.math, where it has
already been thoroughly answered.

In short, at least in version 5: The two integrals do not give the same
result, and for the first integral, Mathematica says "Unable to check
convergence."

David Cantrell


  • Prev by Date: Comparison of Mathematica on Various Computers
  • Next by Date: Numerical Optimization of
  • Previous by thread: Something wrong with this integral (see text)
  • Next by thread: Re: Something wrong with this integral (see text)