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Math Help - Polar coordinates

  1. #1
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    Polar coordinates

    Find the polar coordinates corresponding to the point for which the rectangular coordinates are (2,-5), correct to 3 significant digits.

    How do I start this problem?
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  2. #2
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    Polar coordinates are (r, {\theta})

    Therefore, r=\sqrt{2^{2}+(-5)^{2}}

    {\theta}=tan^{-1}(\frac{-5}{2})
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  3. #3
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    r = 5.39

     \theta = -68.2\;degrees\Longrightarrow 360 + -68.2 = 291.8\;degrees

    Should I write my answer has (5.39,\;291.8\;degrees)

    Or change the 291.8\;degrees to radians?

    Which would give 291.8 \;degrees = 5.09 \;radians

    So the answer would be (5.39,\; 5.09\; radians)? Or the first one I listed?
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  4. #4
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    Polar coordinates are generally given in degrees instead of radians.
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  5. #5
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    Quote Originally Posted by galactus View Post
    Polar coordinates are generally given in degrees instead of radians.
    I really doubt that that is a true statement.
    I for one, advocate dropping the use of degrees in mathematics.
    My rational is simple: radians are numbers.
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  6. #6
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    You are certainly right, Plato. I don't know what's wrong with me. Must've been a brain fart. I was actually thinking the other way, but posted the opposite.
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  7. #7
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    Should I write my answer as this (5.39,\; 5.09\; radians) or (5.39,\;5.09)

    Should I write radians in my answer or no?
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  8. #8
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    Quote Originally Posted by Shinjiro View Post
    Should I write my answer as this (5.39,\; 5.09\; radians) or (5.39,\;5.09)

    Should I write radians in my answer or no?
    These questions have been addressed via response to pm.
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