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Homework Help: Integral of unit impulse function?

  1. Apr 30, 2017 #1
    1. The problem statement, all variables and given/known data

    let's use this symbol to denote the unit impulse function δ
    When integrating the unit impulse function (from negative infinity to infinity) ∫δ(t) dt I know that this results in a value of 1 and is only nonzero at the point t = 0.

    However for example take this integral into consideration ∫δ(t) e-jωt
    since the delta function is only nonzero at the point zero, we only evaluate this multiplication at the point 0 which yields e0 which is 1.

    but how can we do that, the integral involves two functions dependant on time shouldn't we integrate from limits for example 0- to 0+ and integrate it by parts or something like that?

    2. Relevant equations

    ∫δ(t) = 1 at t =0
    3. The attempt at a solution

    My attempt is attempting to explain it above
    Thank you
  2. jcsd
  3. Apr 30, 2017 #2


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    There are a few different ways to put the Derac delta function (generalized function, distribution) on a solid theoretical basis (see https://en.wikipedia.org/wiki/Dirac_delta_function). The result and goal of all of them is that ∫δ(t)f(t)dt = f(0).
  4. Apr 30, 2017 #3
    thank you, you were very helpful....
    loving the profile pic btw!!!
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