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Math Help - Unit circle - Convert cos to sin

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    Unit circle - Convert cos to sin

    What is cos 480 in terms of sin?
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  2. #2
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    Quote Originally Posted by nerdzor View Post
    What is cos 480 in terms of sin?
    \cos (480 ^\circ) = -\frac{1}{2}
    \sin ^{-1} (-\frac{1}{2}) = -30^\circ = 210^\circ =330^\circ= 570^\circ

    But for unit circle, we select -30^\circ as we are measure as close to zero as possible. In other words, the range of \sin ^{-1} is restricted to [–90, 90].
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