Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2013

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

Search the Archive

Re: Simplify a complex expression

  • To: mathgroup at smc.vnet.net
  • Subject: [mg130442] Re: Simplify a complex expression
  • From: Peter Pein <petsie at dordos.net>
  • Date: Thu, 11 Apr 2013 04:13:08 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • Delivered-to: l-mathgroup@wolfram.com
  • Delivered-to: mathgroup-newout@smc.vnet.net
  • Delivered-to: mathgroup-newsend@smc.vnet.net
  • References: <kk4pni$lpa$1@smc.vnet.net>

Am 11.04.2013 00:39, schrieb Polal2is:
> Dear all,
> I have a cumbersome complex expression to simplify the problem is that Conjugate[z] and z are always split I would like a simplified expression involving Abs[z]^2
> as much as possible. How can I tell Mathematica to do it ?
> --
> Thanks a lot in advance
>

Hi,

  tell ComplexExpand that z is a complex number and select Abs and Log 
as target functions:

In[1]:= ComplexExpand[z + Conjugate[z], z,
  TargetFunctions -> {Abs, Log}]

Out[1]= z + Abs[z]^2/z

if this leads to too many Logs, try

In[2]:= z + Conjugate[z] + ArcTan[I z] /. Conjugate :> (Abs[#]^2/# &)

Out[2]= z + Abs[z]^2/z + I ArcTanh[z]

instead.

hth,
   Peter



  • Prev by Date: computation SeriesCoefficient
  • Next by Date: Re: 'show' command
  • Previous by thread: Simplify a complex expression
  • Next by thread: Re: Separating space and time functions