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Coefficents of terms in an expression containing the matching string

  • To: mathgroup at smc.vnet.net
  • Subject: [mg117984] Coefficents of terms in an expression containing the matching string
  • From: Chelly <chelly85086 at gmail.com>
  • Date: Thu, 7 Apr 2011 08:05:33 -0400 (EDT)

I have two questions. The solutions may be very simple, but since I am a Mathematica novice, need some guidance.
 
1) I have an expression:
 
y = 0.5*u*exp(-2 I d1 - d2 - I d4 - phi) -
     0.5*k2*k3*u*exp(-I d2 - I d4 - phi) -
     0.5*k2*k4*u*exp(-I d2 - Id 3 - I phi) ;
 
What command should I use to get just the amplitude of each term, i.e excluding the exponential - exp(). In this case, the results needs to be
{0.5*u, 0.5*k2*k3*u, 0.5*k2*k4*u)
 
2) The second question is along similar lines. I have an expression and I need to find out the terms that have k2^2 in the amplitude
 
y = 0.5*u*exp(-2 I d1 - d2 - I d4 - phi) -
     0.5*k2^2*k3*u*exp(-I d2 - I d4 - phi) -
     0.5*k2*k4*u*exp(-I d2 - Id 3 - I phi)  -
     0.5*k2^2*k5*v*exp(-I d2 - Id 3 - I phi) ;
 
In this case, the answer is the second and last term:
0.5*k2^2*k3*u*exp(-I d2 - I d4 - phi) -
  0.5*k2^2*k5*v*exp(-I d2 - Id 3 - I phi)


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