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Help with Piecewise function, i had a bronchitis!

  1. Jan 10, 2007 #1
    1. The problem statement, all variables and given/known data
    I had a bronchitis the past week, and I have no idea what to do with this problem, my teacher gave us two problems out of 28 from the upcoming quiz, and this is one of the two.

    What the following absolute value using a piecewise function?

    Express the area of a rectangle with a perimeter of 100 with 1 size as length is x.

    Any help would be appreciate!
  2. jcsd
  3. Jan 10, 2007 #2


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    Presumably you textbook defines "piecewise". That is a function that is defined by a specific formula on one interval and then another formula on second formula.

    Also you should know that |x|= x if x>= 0 and |x|= -x if x< 0. In particular, |x+5|= x+ 5 if x+6>=0 and |x+5|= -(x+5) if x< 0.

    Okay, for what values of x is x+5>=0? What is |x+5|+ 2 there? For what values of x is x+5> 0? What is |x+5|+ 2 there?
  4. Jan 18, 2007 #3
    Dont you mean |x+5|=x+5 if x+5>=0 and |x+5|=-(x+5) if x<-5.
  5. Jan 18, 2007 #4


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    Yes, of course, thank you. The 6 is too close to the 5 on a keyboard!
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