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Math Help - Inverse Circular Function, help!!!

  1. #1
    nee
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    Inverse Circular Function, help!!!

    y=cot-1(-.92170128)
    Last edited by ThePerfectHacker; September 3rd 2008 at 09:30 PM.
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  2. #2
    Senior Member Spec's Avatar
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    What's the question exactly?
    Last edited by Spec; August 23rd 2008 at 06:21 PM. Reason: nvm
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  3. #3
    nee
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    According to the text the answer should come up to 2.3154725 in radian mode.

    The text states: "We take the inverse tangent of the reciprocal to find the inverse cotangent".

    I therefore punch in:

    tan-1(1/-0.92170128)

    like the examples show me but I get:

    -0.826120119
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  4. #4
    Senior Member Spec's Avatar
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    You were using the correct method: cot^{-1}(z) = tan^{-1}(\frac{1}{z})

    The book's answer is -0.826120119 	+ \pi


    I should probably mention that they've given this answer because arccotangent's range is 0 < y < \pi
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  5. #5
    nee
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    OK I just fugured it out:

    In degree mode I punched in:

    tan-1(1/-0.92170128)
    = -47.33319621

    -47.33319621 + 180 (which is ∏ radians)
    = 132.6668038

    132.6668038/180
    = 0.737037799

    0.737037799 x
    = 2.31572534

    but I can't fugure out how to get the answer strait into radians?
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  6. #6
    nee
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    Oh ok. Thanks Spec, I was almost there.

    nee
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