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Homework Help: Volume of

  1. May 9, 2005 #1
    Can anybody help me find the volume y=sinx, bounded by the y axis, and the line y=1. The axis of revolution is the line y=1.

    I tried so many times and I cant find the correct answer, in the sheet it says (pie^2)/2 - 2pie
     
  2. jcsd
  3. May 9, 2005 #2

    OlderDan

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    What method are you using, and what are you integrating?
     
  4. May 9, 2005 #3
    [int a=0 b=1] pie(arcsiny)^2 dy

    disk method.
     
  5. May 9, 2005 #4
    I don't know if I did good, cause I'm uncapable of integrating it. :cry:
     
  6. May 9, 2005 #5
    try cylindrical shell method
     
  7. May 9, 2005 #6
    In my paper it says use disk method. :cry:
     
  8. May 10, 2005 #7

    OlderDan

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    I don't think you are looking at it right. As I see it, the radius of a disk centered on the axis of rotation is 1 - sin x and the thickness of the disk is dx. The integral runs from the y-axis (x = 0) to the value of x at the intersection of y = 1 with y = sin x.
     
  9. May 10, 2005 #8
    I was thinking the same thing, and maybe it's just me, but if you finish integrating that, won't you get an answer that's off somewhat? (I think by about +[tex]\textstyle{\frac{\pi^2}{4}}[/tex], otherwise I'm totally and utterly wrong :yuck: )
    cmab, can you doublecheck that answer that your book states?
     
    Last edited: May 10, 2005
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