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Homework Help: Easy Laplace Transform

  1. Dec 6, 2009 #1
    1. The problem statement, all variables and given/known data
    Find the inverse Laplace Transform of (9s+5)/(s2-9) given s>3

    2. Relevant equations
    I have a table of Laplace Transforms.
    it says "sinh at" goes with a/(s2-a2) and "cosh at" goes with s/(s2-a2)

    3. The attempt at a solution
    I know how to split it up and find the inverse Laplace Transform but I don't know what it means by "cosh". I assume it is some variation of cosine? Someone said it means degrees but I don't see how that would change the problem.
  2. jcsd
  3. Dec 6, 2009 #2
    cosh(x) = 1/2 [exp(x) + exp(-x)]

    sinh(x) = 1/2 [exp(x) - exp(-x)]
  4. Dec 6, 2009 #3
    thanks, apparently the professor somewhat explained this but I missed it.
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