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Homework Help: Find energy of signal

  1. Aug 18, 2010 #1
    1. The problem statement, all variables and given/known data

    x(t) = e(-2t) * u(t)

    Ex = x2(t) dt

    Attached is the work I have done. Got stuck towards the end.
     

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  2. jcsd
  3. Aug 19, 2010 #2
    [tex](e^{-2x})^2 = e^{-2x}e^{-2x}=e^{-2x-2x}=e^{-4x}[/tex]
    or you can use the power property associated with exponents and instantly say
    [tex](e^{-2x})^2=e^{2(-2x)}=e^{-4x}[/tex]
    I'm assuming the exponential being squared is what messed you up, and I'm assuming you can take it from here.
     
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