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Help with triple integration problem

  1. Aug 25, 2005 #1
    hey! i need some help with a triple integration problem using spherical coordinates. it's the volume of a small part of a sphere. rho from 5 to 6, phi from pi/6 to pi/4 and theta from pi/4 to pi/3.

    i got an answer of (-91/72) x pi x (sqrt(2)-sqrt(3))...am i right? Thanks!
  2. jcsd
  3. Aug 25, 2005 #2


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    Well, the answer ought to be:
    So, if your answer is just a simplification of this, then it is correct.

    Yup, it is correct.
    Last edited: Aug 25, 2005
  4. Aug 25, 2005 #3
    Hey thanks arildno :)

    but one question..

    shouldnt it be cos(pi/4)-cos(pi/6) instead of cos(pi/6)-cos(pi/4)?
  5. Aug 25, 2005 #4
    No, since:

    [tex]\int_{\frac{\pi}{6}}^{\frac{\pi}{4}} sin\phi d\phi = [-cos\phi]_{\frac{\pi}{6}}^{\frac{\pi}{4}} = -cos(\frac{\pi}{4}) - (-cos(\frac{\pi}{6})) = cos(\frac{\pi}{6}) - cos(\frac{\pi}{4})[/tex]
    Last edited: Aug 25, 2005
  6. Aug 26, 2005 #5
    oh ok...forgot about the negative. thanks!
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