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Math Help - Polar form double integral

  1. #1
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    Polar form double integral

    The question

    I have the region x^2 + (y - 1)^2 = 1 which is a circle above the x-axis.

    I want to describe using polar co-ordinates, but I'm a little stuck. I realise that it goes from 0 to Pi, but the behaviour of the radius I'm not sure of.

    Any assistance would be great!
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  2. #2
    A Plied Mathematician
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    Just plug in the usual substitution and simplify. What do you get?
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  3. #3
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    What do you mean by usual substitution?
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  4. #4
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    Seriously?

    x = r\cdot\cos(\theta)

    y = r\cdot\sin(\theta)

    x^{2} + y^{2} = r^{2}
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  5. #5
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    Quote Originally Posted by TKHunny View Post
    Seriously?

    x = r\cdot\cos(\theta)

    y = r\cdot\sin(\theta)

    x^{2} + y^{2} = r^{2}
    Thank you, but you could have refrained from using such a condescending tone. If I knew what the "usual substitution" was, then I wouldn't have asked the question in the first place.

    Anyway, is the solution r = 2sin(\theta)?
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  6. #6
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    Quote Originally Posted by Glitch View Post
    Anyway, is the solution r = 2sin(\theta)?
    That's what I get.
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  7. #7
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    Quote Originally Posted by Glitch View Post
    Thank you, but you could have refrained from using such a condescending tone.
    I do have trouble with that. We all have little holes in our education. Some are just a little more out of place than others and they strike me as odd.
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