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Proper way to write this math

  1. Dec 27, 2011 #1
    I have a situation where I have two formulas that relate together but do not really transition from one to the other and I'm not sure how to properly write this as a single formula.

    I have these two cases:
    [itex]when \ b<100: a=b*4[/itex]

    [itex]when \ b>=100: a=\frac{b}{4}[/itex]


    I just need a nicer more professional way of writing that as one formula.

    Thanks.
     
  2. jcsd
  3. Dec 28, 2011 #2
  4. Dec 28, 2011 #3
    Perfect. Thank you!!
     
  5. Dec 28, 2011 #4

    HallsofIvy

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    Science Advisor

    Or, if you prefer it on one line,
    [tex]a(b)= 4b+ \left(\frac{4}{b}- 4b\right)H(b- 100)[/tex]
    where H(x) is the "Heviside step function" which is 0 for x< 0, 1 for [itex]x\ge 0[/itex].
     
  6. Dec 28, 2011 #5
    You math kids, and just as I was feeling clever too...
     
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