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Math Help - polar coordinates

  1. #1
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    polar coordinates

    Find the area of the region bounded by r = 3 + 2sin(theta)

    heres an example pic that comes with the problem also: http://us.st11.yimg.com/us.st.yimg.c...s_1932_3273205

    need help.
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  2. #2
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    That picture makes as much sense as division by zero.
    Look at my improved, better, nicer, greater picture below.

    You need to find,
    INT INT 1*dA
    Where the region is the polar figure shown below.

    The bounds for theta are from 0 to 2*pi because we condisder the full figure. And the bounds for r are 3+2sin(theta) and 0 because there is no interior figure.
    Thus,
    INT (from 0 to 2*pi) INT (from 0 to (3+2sin(theta) ) r dr d(theta)
    Attached Thumbnails Attached Thumbnails polar coordinates-picture13.gif  
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  3. #3
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    sorry, very new to coordinate systems, is INT for integral, integer, or interior?

    thanks.
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  4. #4
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    Hello, rcmango!

    By the way, you can stop posting the blank graph paper, okay?


    Find the area of the region bounded by: r = 3 + 2sinθ

    From the questions you posted, it seems that you know nothing about polar curves.

    Are you familiar with the cardioid and its variations so you can make a sketch?

    Do you know the area formula for polar coordinates?

    . . . . . . . . . .β
    . . A . = .
    r dθ
    . . . . . . . . . α


    This graph is symmetric to the 90 line (the "y axis")
    . . so we can integrate from -π/2 to π/2 and multiply by 2


    . . A . = . 2 x
    (3 + 2sinθ) dθ

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  5. #5
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    i moved this to urgent section.
    Last edited by rcmango; February 15th 2007 at 07:19 PM.
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