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Math Help - Trig equations

  1. #1
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    Trig equations

    How many solutions exist for the equation 3Cos 2x=-3 in the interval 0<=x<=2Pi The 2 confuses me. How do I adjust for that? Thanks
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  2. #2
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    3\cos(2x) = -3

    \cos(2x) = -1

    since 0 \leq x \leq 2\pi , then 0 \leq 2x \leq 4\pi

    2x = \pi

    x = \frac{\pi}{2}

    2x = 3\pi

    x = \frac{3\pi}{2}
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