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Homework Help: Integration with a unit step function

  1. Feb 15, 2010 #1
    Hi,

    i have a problem with integration a function with a unit step function.

    1. The problem statement, all variables and given/known data
    Given,

    eafe.JPG

    Refer to the image, i dun understand is that u(t) is equal to 1 from a definite integration from -[tex]\infty[/tex] to [tex]\infty[/tex] since u(t)=1 from -[tex]\infty[/tex] to 0 and u(t)=0 from 0 to [tex]\infty[/tex].


    Thanks.
     
  2. jcsd
  3. Feb 15, 2010 #2

    Mark44

    Staff: Mentor

    Isn't it the other way around like in your drawing? I.e., that u(t) = 0 for t < 0 and u(t) = 1 for 0 <= t < infinity?

    That means that
    [tex]\int_{-\infty}^{\infty} g(t) u(t)dt = \int_0^{\infty} g(t) dt [/tex]
     
  4. Feb 15, 2010 #3
    so if i have muliplication of few unit step function like in the image below,

    faea.JPG

    am i right this way?
     
  5. Feb 16, 2010 #4

    vela

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Education Advisor

    Ayuh.
     
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