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MathGroup Archive 1996

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Re: Complex numbers

  • To: mathgroup at
  • Subject: [mg5445] Re: Complex numbers
  • From: ianc (Ian Collier)
  • Date: Sat, 7 Dec 1996 00:26:21 -0500
  • Organization: Wolfram Research, Inc.
  • Sender: owner-wri-mathgroup at

In article <57tvhr$k0f at>, Wouter Dobbelaere
<Wouter.Dobbelaere at> wrote:

> Hi,
> Is there a way to calculate the real or imaginary part of a complex
> expression symbolically (assuming real numbers as parameters) like:
> Re[x + I y] = x
> The standard Re function doesn't seem to allow that. Maybe some
> extensions exist?
> Regards,
> Wouter Dobbelaere

You can use Complex Expand to do what you want:

    expr= Re[x + I y]



"ComplexExpand[expr] expands expr assuming that all variables are real. 
ComplexExpand[expr, {x1, x2, ... }] expands expr assuming that variables 
matching any of the xi are complex."



I hope this helps.


Ian Collier
Wolfram Research, Inc.
tel:(217) 398-0700   fax:(217) 398-0747    ianc at
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