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    3.
    A curve has equation: Y=1/[(x^2)+1]

    The shaded region R is bounded by the curve, the coordinate axis and the line x=2.

    a) Use the trapezium rule with 4 strips of equal width to estimate the area R.
    [DONE this and got 1.10 to 3sfg]

    The cross-section of a support for a bookshelf is modelled by R with 1 unit on each axis representing 8 cms. Given that the support is 2 cm thick,

    b) Find an estimate for the volume of the support.

    I understand how to get b), PLS HELP!!
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    volume = cross-section * length
    volume = 1.1units * 2units
    volume = 2.2units
    1unit = 8cm..
    volume = 2.2 * 8 = 17.6cm^3
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    Ok, that's exactly what I had done and the answer is incorrect.
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    I think you have done part A wrong, 1.1 doesnt look right.

    /edit
    Y=1/[(x^2)+1]

    when x=0, y = 1/1 = 1
    when x=1, y = 1/2 = 0.5
    when x=2, y = 1/(4+1) = 1/5 = 0.2
    area of trapezium = (a+b)*h/2
    first trapezium = (0.5+1)*1/2 = 0.75
    second trapezium = (0.5+0.2)*1/2 = 0.35
    area roughly = 1.1units^2


    hmmm
 
 
 
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Updated: April 11, 2006
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