Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2007
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2007

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

Search the Archive

Solving a Integral

  • To: mathgroup at smc.vnet.net
  • Subject: [mg78043] Solving a Integral
  • From: ehrnsperger.b at pg.com
  • Date: Thu, 21 Jun 2007 06:03:03 -0400 (EDT)

I need help in solving the following integral:

Integral = 1/(beta^alpha* Gamma[alpha]) *
Integrate[x^(alpha-1)*Exp[-x/beta]/(1+Exp[-a*x-b]),{x,0, infinity},
Assumptions: (alpha> 0)||(beta > 0)||(a > 0)||(b <0)]

The Integral is approximately 1/(beta^alpha* Gamma[alpha])
*1/(1+Exp[-a*alpha*beta-b]) + Order[alpha*beta^2]

However, I would like to have an exact analytical solution, and I am
failing to convince Mathematica to give me the solution. Is there a way to 
ask Mathematica to give the solution as a series expansion of my
approximate solution?

Thanks so much for your help,

Bruno

Dr. Bruno Ehrnsperger
Principal Scientist

Procter & Gamble Service GmbH
Sulzbacherstr.40
65824 Schwalbach
Germany

fon +49-6196-89-4412
fax +49-6196-89-22965
e-mail: ehrnsperger.b at pg.com
internet: www.pg.com

Gesch=E4ftsf=FChrer: Otmar W. Debald, Gerhard Ritter, Dr. Klaus Schumann,
Willi Schwerdtle
Sitz: Sulzbacher Str. 40, 65824 Schwalbach am Taunus, Amtsgericht:
K=F6nigstein im Taunus HRB 4990



  • Prev by Date: Mind+Mathematica
  • Next by Date: Re: question
  • Previous by thread: Re: Mind+Mathematica
  • Next by thread: Re: Solving a Integral