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Re: Questions about "collecting" complex exponentials and simplifying expressions

• To: mathgroup at smc.vnet.net
• Subject: [mg53055] Re: Questions about "collecting" complex exponentials and simplifying expressions
• From: "David Winterbottom" <david.winterbottom at gmail.com>
• Date: Wed, 22 Dec 2004 04:52:45 -0500 (EST)
• References: <6hpd0u$d8r@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

In my experience with weakly nonlinear analyses, the best way to
proceed is to define the conjugate of A as a separate variable.  For
example, if we set
Y = A[x,X,t,T] Exp[I(wt+kx)] + A^*[x,X,t,T] Exp[-I(wt+kx)]
then simply running
Expand[Y^2]
yields an answer in acceptable form.  Of course, instead of "A
Conjugate[A]", you now have "A[x,X,t,T] A^*[x,X,t,T]".