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Math Help - Solving a trig equation

  1. #1
    Member >_<SHY_GUY>_<'s Avatar
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    Solving a trig equation

    Can someone please help me with this problem? Thank you

    If possible, find the exact solutions algebraically

    (sin2x + cos2x)^2 =1
    Last edited by mr fantastic; December 9th 2009 at 07:52 PM. Reason: Changed post title
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  2. #2
    Flow Master
    mr fantastic's Avatar
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    Quote Originally Posted by >_<SHY_GUY>_< View Post
    Can someone please help me with this problem? Thank you

    If possible, find the exact solutions algebraically

    (sin2x + cos2x)^2 =1
    Expand the left hand side and apply the Pythagorean Identity. After simplifying, the equation becomes 2 \sin (2x) \cos (2x) = 0 which can be easily solved in a number of ways.
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  3. #3
    Super Member 11rdc11's Avatar
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    Quote Originally Posted by >_<SHY_GUY>_< View Post
    Can someone please help me with this problem? Thank you

    If possible, find the exact solutions algebraically

    (sin2x + cos2x)^2 =1
    yes make the sub u =2x

    The equation then turns into

    (\sin{u} +\cos{u})^2 =1
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  4. #4
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    I have removed my method since the method submitted by mr fantastic is much more efficient than mine.
    Last edited by NOX Andrew; December 10th 2009 at 04:10 AM.
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