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MathGroup Archive 2007

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Re: Improper Integral & Mathematica

  • To: mathgroup at smc.vnet.net
  • Subject: [mg80592] Re: [mg80577] Improper Integral & Mathematica
  • From: DrMajorBob <drmajorbob at bigfoot.com>
  • Date: Sun, 26 Aug 2007 23:06:29 -0400 (EDT)
  • References: <20084428.1188114597855.JavaMail.root@m35>
  • Reply-to: drmajorbob at bigfoot.com

Here's the indefinite integral:

Integrate[(E^x)/(1 + E^(2 x)), x]

ArcTan[\[ExponentialE]^x]

and here's the definite one:

Integrate[(E^x)/(1 + E^(2 x)), {x, -Infinity, Infinity}]

\[Pi]/2

The substitution is u = E^x in

Integrate[1/(1 + u^2), u]

ArcTan[u]

Bobby

On Sun, 26 Aug 2007 02:11:33 -0500, <expizzaiolo at gmail.com> wrote:

> Hi all !   :-)
>
> how to solve:
>
> Integrate[(e^x) / (1 + e^(2x)), {x, - Infinity, + Infinity }]
>
> using Mathematica? I'm trying "e^x = t" but won't work...
>
>
>
> TNX!
>
>
>



-- =

DrMajorBob at bigfoot.com


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