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Homework Help: Finding the area between 3 functions

  1. Oct 8, 2011 #1
    Hi all, I've been attempting this problem for hours and I believe I am using the correct method, but I keep on getting the wrong answer, ANY help as to what I am doing wrong is greatly appreciated.

    The question is:

    Sketch the region enclosed by the given curves. Decide whether to integrate with respect to x or y. Then find the area of the region.
    2y = 3sqrt(x) , y = 5, and 2y + 4x = 7

    I've plotted the graph, and found the intersection points, with are : x= -3/4 , x=1 x= 11.11111

    I integrated with respect to X (I know that y would be easier, but I'm not too sure how to do that yet), therefore, the areas were:

    step 1: int. between -3/4 to 1 with the function to be integrate being : 5-(-2x+7) and

    step 2: int. between 1 to 11.11111111 with the function to be integrated being : 5-([3sqrt(x)]/2)

    I integrated step 1 (2x-2, integrate that, and I got x^2-2x), when plugging in the numbers, I got -3.0625

    I integrated step 2, and got 5x-x^3/2, when plugging in the numbers, I got 14.51851852

    I added both areas and got 11.45601.

    What am I doing wrong?..
     
  2. jcsd
  3. Oct 9, 2011 #2

    ehild

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    Homework Helper

    Divide 7 by two, too.

    ehild
     
  4. Oct 9, 2011 #3
    ahh, I can't believe I missed that. :X!! thanks a million ehild
     
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