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MathGroup Archive 2004

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Complex Numbers

  • To: mathgroup at
  • Subject: [mg47425] Complex Numbers
  • From: Alejandro Vizcarra <gebankos at>
  • Date: Sun, 11 Apr 2004 04:44:03 -0400 (EDT)
  • Sender: owner-wri-mathgroup at

I always have problems when dealing with complex numbers.  How can i
work with Mathematica in such a way that every expression will
be considered real unless it is declared explicitly complex (like a = 3 + 4 I ) ?
For example if I type 

Re[ComplexExpand[ Exp[a I] Exp[b I]]]

I get the answer

-Im[Sin[ a+b]]+Re[Cos[a+b]]

Instead of simply Cos[a+  b]


Alejandro Vizcarra

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