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Math Help - Trig. Equation

  1. #1
    Junior Member CONFUSED_ONE's Avatar
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    Trig. Equation

    OKay, so how would this equation be solved,
    cosx-2sinxcosx=0

    so I've tried this way...
    cosx-2sinxcosx=0
    cosx(1-2sinx)=0
    and after that, i'm stuck.
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  2. #2
    MHF Contributor
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    Well this has multiple answers now doesn't it? You've factored correctly. You know that you're equation will be zero when cos(x)=0 and when 1-2sin(x)=0. So solve for both. I'll start you. The first time cos(x)=0 starting from 0 and moving positively is at \frac{\pi}{2} and it will do so at every at every \pi after that. So I would write one zero as \frac{\pi}{2}+k\pi where k is any integer.
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  3. #3
    Junior Member CONFUSED_ONE's Avatar
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    Oh yes, silly me. I forgot about cosx=0. Thank you very much Jameson!
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