Re: Complex Numbers

*To*: mathgroup at smc.vnet.net*Subject*: [mg47437] Re: [mg47425] Complex Numbers*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Mon, 12 Apr 2004 03:44:51 -0400 (EDT)*References*: <200404110844.EAA07722@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

On 11 Apr 2004, at 17:44, Alejandro Vizcarra wrote: > Hi,: > > 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] > > Thnx! > > > Alejandro Vizcarra > > Not Re[ComplexExpand[ Exp[a I] Exp[b I]]] but ComplexExpand[Re[Exp[a I] Exp[b I]]] Cos[a+b] Andrzej Kozlowski Chiba, Japan http://www.mimuw.edu.pl/~akoz/

**References**:**Complex Numbers***From:*Alejandro Vizcarra <gebankos@prodigy.net.mx>