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Re: Difficulties with Re

• To: mathgroup at smc.vnet.net
• Subject: [mg98335] Re: [mg98349] Difficulties with Re
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Wed, 8 Apr 2009 02:44:56 -0400 (EDT)
• Organization: Mathematics & Statistics, Univ. of Mass./Amherst
• References: <200904060905.FAA26352@smc.vnet.net>
• Reply-to: murray at math.umass.edu

ComplexExpand is your friend:

   ComplexExpand[Re[Exp[x + I y]]]
E^x*Cos[y]

   ComplexExpand[Re[Exp[(x + I y)^2]]]
E^(x^2 - y^2)*Cos[2*x*y]


Aaron Fude wrote:
> Hi,
> 
> Of the following two expressions, the first "works", while the second
> doesn't. How does one make it work?
> 
> Assuming[x > 0 && y > 0, Re[Exp[x + I y]] // Simplify]
> Assuming[x > 0 && y > 0, Re[Exp[(x + I y)^2]] // Simplify]
> 
> Many thanks in advance,
> 
> Aaron
> 

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

• References:
  • Difficulties with Re
    • From: Aaron Fude <aaronfude@gmail.com>