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Topic: Real and Imaginary Parts of complex functions
Replies: 3   Last Post: Feb 27, 2013 3:04 AM

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Bob Hanlon

Posts: 906
Registered: 10/29/11
Re: Real and Imaginary Parts of complex functions
Posted: Feb 27, 2013 3:04 AM
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Just use ComplexExpand with assumes that all variables are Reals
unless otherwise specified.

Re[x + y*I] // ComplexExpand

x

Re[1/(x + y*I)] // ComplexExpand

x/(x^2 + y^2)


Bob Hanlon


On Tue, Feb 26, 2013 at 1:09 AM, Brentt <brenttnewman@gmail.com> wrote:
>
> 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?
>
>





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