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    It's a trigonometry question from c3

    Give exact answers in terms of pi
    2(1-cos2thetta) = tan thetta in the range of 0<thetta<pi

    I think you use one of
    cos^2thetta- sin^2thetta
    1-2sin^2thetta
    2cos^2thetta - 1
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    (Original post by jkljeril)
    It's a trigonometry question from c3

    Give exact answers in terms of pi
    2(1-cos2thetta) = tan thetta in the range of 0<thetta<pi

    I think you use one of
    cos^2thetta- sin^2thetta
    1-2sin^2thetta
    2cos^2thetta - 1
    Use the first one, as well as 1 \equiv \sin^2(\theta) + \cos^2(\theta)
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    the tanthetta on the right hand side would still be there
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    (Original post by jkljeril)
    the tanthetta on the right hand side would still be there
    Yeah so get rid off it by multiplying both sides by \cos(\theta)
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    what do i do now?

    4sin^2 thetta cos thetta = sin thetta
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    (Original post by jkljeril)
    what do i do now?

    4sin^2 thetta cos thetta = sin thetta
    Divide by \sin(\theta), perhaps?

    Spoiler:
    Show


    Usually we don't divide, but do you see why we CAN divide here?

 
 
 
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