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Homework Help: Help with Laplace Transform

  1. Apr 18, 2010 #1
    1. The problem statement, all variables and given/known data
    Let f(t) denote a causal signal. Show that L+ {f(−at)} = 0 for any a > 0.

    2. Relevant equations



    3. The attempt at a solution
    I know that the laplace{f(at)} = 1/a*F(s/a)

    but by simply placing -a whenever determining the Laplace, my signs gets confused within the integral. So my answer is

    1/-a*F(s/a) and not 0

    Does anyone know how to do this so the L+ {f(−at)} = 0 ?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Apr 18, 2010 #2

    LCKurtz

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    Science Advisor
    Homework Helper
    Gold Member

    What is a "causal signal"?

    What does L+ {f(−at)} mean?
     
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