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Math Help - Solving a trig equation #2

  1. #1
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    Solving a trig equation #2

    Could anyone help on this trig identity? I have a quiz tomorrow and am unsure on this one.

    2 cos squared x- 5 cosx+ 2= 0

    Any help is appreciated!
    Last edited by mr fantastic; February 16th 2011 at 05:38 PM. Reason: Re-titled.
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  2. #2
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    Do you mean solve this equation for \displaystyle x ?

    If so make \displaystyle u=\cos x and solve the quadratic \displaystyle  2u^2-5u+2=0
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  3. #3
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    Quote Originally Posted by powerduffgirL View Post
    Could anyone help on this trig identity? I have a quiz tomorrow and am unsure on this one.

    2 cos squared x- 5 cosx+ 2= 0
    ... recommend you find out the difference between identities and conditional equations.
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