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Volume ( is the set up OK?)

  1. Sep 22, 2013 #1
    1. The problem statement, all variables and given/known data

    Find the volume obtained by rotating the regon boudned by the given curve about the specified axis

    2. Relevant equations

    3. The attempt at a solution

    y = secx, y = cosx, 0 <= x < = pi/3

    This is what I set up.

    V = ∏∫ (secx +1 )^2 - (cosx +1)^2 dx

    I said R was secx - (-1) and r is cosx -(-1)
  2. jcsd
  3. Sep 22, 2013 #2


    Staff: Mentor

    Looks OK, assuming you are rotating the region about the line y = -1, which is info you didn't provide. When you post a problem, remember to include the complete problem statement.
  4. Sep 22, 2013 #3
    Yeah I'm doing it about x = -1. Thanks dude. Sorry.
  5. Sep 22, 2013 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Why the 1's?
    The radii in the cross-sectional disks are specified with the function values.
    Thus, your integrand is sec^2(x)-cos^2(x)

    I assumed it was about y=0
  6. Sep 22, 2013 #5
    Yeah well that is because I made a mistake in my post and left out that is was about y = -1.
  7. Sep 22, 2013 #6


    Staff: Mentor

    Apparently you aren't clear, either.
  8. Sep 22, 2013 #7
    Ha. Lack of sleep
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