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Re: complex numbers

  • To: mathgroup at smc.vnet.net
  • Subject: [mg24445] Re: [mg24396] complex numbers
  • From: BobHanlon at aol.com
  • Date: Tue, 18 Jul 2000 00:58:46 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

In a message dated 7/12/2000 11:29:58 PM, Ruchi5ten at aol.com writes:

>when i ask for the Re or Im parts of the a numerical conjugate, mathematica
>(4.0) does the operation correctly, but for a conjugate made of symbols
>(such as a+bI) it does not recognize whether the variable is real or not.
> i've tried to set the variable with a pattern and a blank to indicate
>them as such (ie a_Real) but still, mathematica doesn't see a difference.
> what can i do to work around the problem?
>

x = a + b*I;

Re[x] // ComplexExpand

a

Im[x] // ComplexExpand

b

Conjugate[x] // ComplexExpand

a - I*b

Simplify[Re[x], Element[{a, b}, Reals]]

a

Simplify[Im[x], Element[{a, b}, Reals]]

b

FullSimplify[Conjugate[x], Element[{a, b}, Reals]]

a - I*b


Bob Hanlon


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