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Homework Help: Equal area question

  1. Apr 1, 2007 #1
    1. The problem statement, all variables and given/known data
    "Find a horizontal line y=k that divides the area between y=x^2 and y=9 into two parts"


    2. Relevant equations



    3. The attempt at a solution
    Found intersection at (-3,9), (3,9)
    Found total area to be 36, half(the area needed for each portion) to be 18. Don't know where to go from here.
     
  2. jcsd
  3. Apr 1, 2007 #2
    Find the two areas as a function of k.
     
  4. Apr 1, 2007 #3
    Can you elaborate more on that? I'm not quite sure what you mean.
     
  5. Apr 1, 2007 #4
    y=k divides the total area into two parts, A1=A1(k) and A2=A2(k). You need to find an expression for each area as a function of k and then find the value of k for which A1(k)=A2(k)
     
  6. Apr 1, 2007 #5

    Hurkyl

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    Don't be intimidated by the variable k -- the fact it's there changes nothing. You know how to compute areas, so compute the area of one of the portions.
     
  7. Apr 2, 2007 #6

    HallsofIvy

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    What is the area of the region bounded by y= k, y= 9 and y= x2? For what value of k is that 18?

    Even simpler: What is the area of the region bounded by y= 0, y= k and y= x2? For what value of k is that 18?
     
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