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Re: declaring variables
Posted:
Sep 13, 1996 1:00 PM
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dh61@rs3.hrz.th-darmstadt.de (Burkhardt Goedde) wrote:
>Dear math users,
>just a simple problem, but I got no answer from thew book.
>Re[x + I y] gives
>Re[x + I y]
>whereas
>Re[2 + 3 I]
>gives 2
>How could I tell Mathematica that x and y are real numbers?
There is a package <<Algebra`ReIm` that lets you specify that given
variables are purely real. Try the following:
In[5]:= Needs["Algebra`ReIm`"]
Im[x]^=0;
Im[y]^=0;
Re[x + I y]
Im[x + I y]
Out[8]= x
Out[9]= y
The up definitions make the assignment associated with x and y rather
than
with Im...
Hope this helps
Vicki
________________________________________________________________________
Victoria Steblina Email: vvs124@rsphy1.anu.edu.au
Optical Sciences Centre Tel: 61 6 249 5129
Australian National University Fax: 61 6 249 5184
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