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Math Help - Exact value for ratio

  1. #1
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    Exact value for ratio

    Hey i need help finding the exact measures for these two trig ratios

    cot(4pi/3)
    cos(-19pi/6)
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  2. #2
    Super Member Quacky's Avatar
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    Re: Exact value for ratio

    Well, how would you solve \tan{\frac{4\pi}{3}}? Can you think of anything equivalent to this? Think of the unit circle - which other value for tan will give an equivalent result?

    For \cos{(\frac{-19\pi}{6})}, it's the same idea. Remember that \cos(x) is periodic every 2\pi radians, so you can keep adding \frac{12}{6}\pi to the value in the brackets and your answer will be unchanged.
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  3. #3
    Junior Member mathbyte's Avatar
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    Post Re: Exact value for ratio

    I bet a diagram of the unit circle will help, too.
    See the one on Wikipedia here.
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