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

MathGroup Archive 2013

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

Search the Archive

Re: Real and Imaginary Parts of complex functions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg129945] Re: Real and Imaginary Parts of complex functions
  • From: Szabolcs HorvÃt <szhorvat at gmail.com>
  • Date: Wed, 27 Feb 2013 03:08:18 -0500 (EST)
  • 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: <kghjhs$s36$1@smc.vnet.net>

On 2013-02-26 06:09:00 +0000, Brentt said:

> Hello,
> 
> I was wondering why this works
> 
> IN[]:= Refine[Re[x + y I], Element[x , Reals] && Element[y , Reals]]
> 
> Out[]:= x
> 
> But this does not
> 
> In[]:= Refine[Re[1/(x + y I)], Element[x , Reals] && Element[y , Reals]]
> 
> Out[]:= Re[1/(x + y I)]
> 
> 
> 
> Is there a nice built in way to get the real and imaginary parts of a
> complex function?

You can use ComplexExpand for this.

In[8]:= ComplexExpand[Re[1/(x + y I)]]
Out[8]= x/(x^2 + y^2)

See also http://mathematica.stackexchange.com/q/9340/12 and the links within.




  • Prev by Date: Re: Real and Imaginary Parts of complex functions
  • Next by Date: A bug-looking behavior during integration
  • Previous by thread: Re: Real and Imaginary Parts of complex functions
  • Next by thread: Manual argument type with MathLink C interface