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Math Help - Please help with these Algebra questions

  1. #1
    Newbie
    Joined
    Jun 2010
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    4

    Please help with these Algebra questions

    Please help me to solve the following equations (giving 1 or 2 solutions):

    sin x = √3 cos x

    sin^2x - cos^2x sin x = 1

    cos 2x + sin x + 1 = 0

    sin 2 x + cos x = 0

    tan^2x + sec x 1 = 0

    Any help no matter how little is much appreciated, I just don't know where to start.

    Thanks in advance.
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  2. #2
    Member
    Joined
    Nov 2009
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    Hints:
    1) divide by cos(x) both sides

    2) subtract 1 on both sides then use the equality cos^2(x)=1-sin^(x)

    3) cos(2x)=cos^2(x)-sin^2(x) and 1=sin^2(x)+cos^2(x)

    4) sin(2x)=2sin(x)cos(x)

    5) tan^2(x)=sec^2(x)+1
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  3. #3
    Newbie hungthinh92's Avatar
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    Virginia, US
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    1) divide by cos(x) both sides

    2) subtract 1 on both sides then use the equality cos^2(x)=1-sin^2(x)

    3) cos(2x)=cos^2(x)-sin^2(x) and 1=sin^2(x)+cos^2(x) cos^2x=1-2sin^2x

    4) sin(2x)=2sin(x)cos(x)

    5) tan^2(x)=sec^2(x)+1
    I just fix something I think you need to clear.
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