Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1997
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1997

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

Search the Archive

Re: Defining Real expressions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg8509] Re: Defining Real expressions
  • From: hans.steffani at e-technik.tu-chemnitz.de (Hans Steffani)
  • Date: Thu, 4 Sep 1997 02:19:55 -0400
  • Organization: University of Technology Chemnitz, FRG
  • Sender: owner-wri-mathgroup at wolfram.com

Marco Beleggia <beleggia at gpxbof.df.unibo.it> writes:

>I must evaluate an Integral in which I'd like to assign real values to
>some parameters, but I don't know how to do that.

>For example, in the following integral (a Fourier Transform): 

>f[x_,p_]=Integrate[y/(x^2+y^2) Exp[-I p y],{y,-Infinity,Infinity}],

>p should be a real parameter. The output given by Mathematica is
>conditioned to Im[p]==0, such as If[Im[p]==0,....,....], which is not
>easy to handle, and I'd like to avoid this complication.

I do not understand the problem:

Integrate[y/(x^2+y^2) Exp[-I p y],{y,-Infinity,Infinity}]

delivers

                               2
     2 1/4               Sqrt[p ] Pi
-I (p )    Sqrt[Pi] Sqrt[-----------]
                              2
                             p
-------------------------------------
                2        2
          Sqrt[p ] Sqrt[x ]
         E


Maybe ComplexExpand[] helps in your case.

h.f.s.
[cc,fup]
--
Hans Friedrich Steffani
Institut fuer Elektrische Maschinen und Antriebe, TU Chemnitz-Zwickau
mailto:hans.steffani at e-technik.tu-chemnitz.de
http://www.tu-chemnitz.de/~hfst/


  • Prev by Date: Re: Limit bug in Calculus\Limit ???
  • Next by Date: C code generation with MMM3.0
  • Previous by thread: Re: Defining Real expressions
  • Next by thread: Re: Defining Real Expressions