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Homework Help: Inverse Laplace

  1. Mar 16, 2008 #1
    1. The problem statement, all variables and given/known data
    Inverse laplace transforms

    F(s)=[tex]\frac{5s-2}{s^{2}(s-1)(s+2)}[/tex]


    2. Relevant equations
    Residue technique

    3. The attempt at a solution

    F(s)=[tex]\frac{5s-2}{s^{2}(s-1)(s+2)} = \frac{k1}{s^{2}} + \frac{k2}{s-1} + \frac{k3}{s+2}[/tex]

    I solved for K1,K2, and K3, which all came to be 1.

    answer=[tex]e^{t}+e^{-2t}+t [/tex]
    textbook answer = [tex]e^{t}+e^{-2t}+t -2[/tex]

    Can someone explain to me how did the -2 come?
     
    Last edited: Mar 16, 2008
  2. jcsd
  3. Mar 17, 2008 #2
    It is very important that I know this. I was told that there was a k4 at the end but for problems we did in control theory class k4 was said to be 0 always and we took it as a rule.

    So I need to know where this -2 came from.
     
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