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Homework Help: Step function

  1. Mar 30, 2005 #1
    I just want to check if I got this right.
    Given this graph, I need to define a step function:
    Code (Text):

             |
    ---------| C
             |
    _________|_______________
             |
          -C |_________
             |
     
    So, my definition is: C[-u(t) + u(-t)].
    Thanks for checking this.
     
  2. jcsd
  3. Mar 30, 2005 #2
    f(x) = {c, x < 0}{-c, x > 0}, f(x) is undef at x = 0, though, |f(0)| = c
     
  4. Mar 30, 2005 #3
    Thanks for reply.

    I understand the form of the function, but this is for an engineering class, so we have to express everything in terms of u(t), etc. So, this is what I need for some-one to double check.
    And they actually never say that there is a discontinuity at 0, because we have to find values for t >=0 and so on.
     
  5. Mar 30, 2005 #4
    I don't think your definition will work so well. Lets say 0<c, and 0<t<c. What is the value of your function? well [tex]u_c(t)=0 \mbox{ for } t<c \mbox{ and } u_c(-t)=0 \mbox{ for } t<c [/tex] since t will just be negative it will still be less than c. So your function will not work in that case. I just worked from left to right to construct the definiton and came up with
    [tex] C[1-2u_c(t)] [/tex]

    Which seems to work for all t in R.

    Regards
     
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