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Estimating area under the graph

  1. Jan 9, 2013 #1
    1. The problem statement, all variables and given/known data

    Estimate the area under the graph of f(x)=3+x^2 from x=−1 to x=2 using six approximating rectangles and right endpoints.

    3. The attempt at a solution

    I've tried this multiple times but can't seem to get it, can someone tell me if i am on the right track?

    i have

    summation [3/6(3+(-1+i/6)^2)]

    where i starts at -1 and increases by .5 passing through (-1,-0.5,0,0.5,1,1.5)

    (I'm not sure about how the i increases)

    Can anyone tell me what i am doing wrong?
  2. jcsd
  3. Jan 9, 2013 #2


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    Staff Emeritus
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    Homework Helper

    Start with a picture of the problem.

    Show the widths and heights of your 6 rectangles.
  4. Jan 9, 2013 #3


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    Science Advisor

    This is an error. Because you are using right endpoints, the heights of the rectangles are determined at -0.5, 0, 0.5, 1, 1.5, and 2.

    I would second SteamKing's suggestion that you actually draw the rectangles. You seem to be trying to apply a formula without understanding it.
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