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Math Help - weird trig problem

  1. #1
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    weird trig problem




    I've never done any like this before help!
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  2. #2
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    Not the best at explaining things but here goes:

    First use the unit circle to find all angles in which sine equals 1/2 and write them down in radians.
    Sine works with the interval equation angle + 2*pi*k
    Since it is double angle (sine2theta) you must use the equation for both of the radians you wrote down before and divide by 2 to get your formulas.
    You then plug in numbers to K to find all occurrences where theta equals anything in the interval 0 to 2pi

    sin2theta = 1/2
    2theta = pi/6 , 5pi/6

    first equation
    2theta = pi/6 + 2*pi*k
    theta = pi/12 + pi*k

    second equation
    2theta = 5pi/6 + 2*pi*k
    theta = 5pi/12 + pi*k

    Try plugging in 0,1,2,3 and so on to both equations and your answer will be all the numbers that are between your interval of 0 and 2pi.

    Hope that helps somewhat, but I'm sure someone else can explain it much better.
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  3. #3
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    surprisingly.. I understand your explanation =D I came out with:

    pi/12, 13pi/12, 5pi/12, and 17pi/12

    I think that's it. Thanks so much for the help!
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