Re: Complex numbers
- To: mathgroup at smc.vnet.net
- 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 wolfram.com
In article <57tvhr$k0f at dragonfly.wolfram.com>, Wouter Dobbelaere
<Wouter.Dobbelaere at rug.ac.be> 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:
In[2]:=
expr= Re[x + I y]
Out[2]=
-Im[y]+Re[x]
In[4]:=
?ComplexExpand
"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."
In[3]:=
ComplexExpand[expr]
Out[3]=
x
I hope this helps.
--Ian
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Ian Collier
Wolfram Research, Inc.
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tel:(217) 398-0700 fax:(217) 398-0747 ianc at wolfram.com
Wolfram Research Home Page: http://www.wolfram.com/
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