MathGroup Archive 2003

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

Search the Archive

Re: Something wrong with this integral (see text)

"Ihor Stealth" <stealth at> 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

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)