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Homework Help: Laplace and inverse laplace transformation of unit step functions u(t).

  1. Feb 5, 2013 #1
    1. The problem statement, all variables and given/known data

    So I have this laplace transformation chart and was a bit unsure about the laplace and inverse laplace of this.

    The unit step function, where u(t) = 0 where t < 0, u(t) = 1 where t > 0.

    The laplace transformation chart that I have has two columns, the column on the left shows f(t) and the column on the right shows inverse laplace{f(t)} = F(s) for the corresponding f(t) on the left. Under f(t), both u(t) and 1 are on the same row as F(s) = 1/s. Does this mean that if I take the inverse laplace of 1/s, I can choose between using 1 or u(t)?

  2. jcsd
  3. Feb 5, 2013 #2


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    The Laplace transform involves the domain [itex]t\in [0,\infty)[/itex]. Both [itex]f(t)=1[/itex] and [itex]u(t)[/itex] are the same on this domain, so there's no ambiguity in computing the inverse Laplace transform.
  4. Feb 5, 2013 #3

    Thats what I thought.
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