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Homework Help: How does one represent this in math

  1. Oct 31, 2008 #1
    How does one represent this in math....

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

    How does one represent the following in mathematical notation:

    if(x >= a) then y = x-a
    else x=0

    2. Relevant equations

    3. The attempt at a solution
    Just y= x-a will not do it because it becomes negative when x is less than a and that is not what I want....
  2. jcsd
  3. Oct 31, 2008 #2


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    Science Advisor
    Homework Helper

    Hi wildman! :smile:

    How about using min or max (or is it inf or sup :rolleyes:)? :wink:
  4. Oct 31, 2008 #3


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    Science Advisor

    Re: How does one represent this in math....

    I'm not sure what you kind of notation you want. I would write that as either
    [tex]y= \left(\begin{array}{c} x- a if x\ge a \\ 0 if x> a\end{array}\right [/tex]

    Or as y= H(x-a)(x-a) where H(x) is the Heaviside step function.
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