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Homework Help: Unit step function

  1. Oct 16, 2008 #1
    1. The problem statement, all variables and given/known data

    Express f(t) = e^t, 0<t<2, using the unit step function

    2. The attempt at a solution

    e^t*u(t-2) is an expression for a graph of the function that is zero untill t=2. My guess is

    e^t*u(t+2)
     
  2. jcsd
  3. Oct 16, 2008 #2

    Dick

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    Homework Helper

    That's not a very good guess. That makes f(-1)=e^(-1). You want to subtract two step functions so you get something that's only nonzero between 0 and 2.
     
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