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Homework Help: Simplifying a trig equation

  1. Nov 7, 2007 #1
    1. The problem statement, all variables and given/known data
    (this is really only part of my problem it's an optimization problem but this is where I'm stuck)
    Find the zeros of: cos^2(x)-sin^(x)+cos(x)

    2. Relevant equations

    3. The attempt at a solution

    I've been trying to use trig identities such as sin^2 + cos^2 = 1 but it's not getting me anywhere I know the answer is pi/3 because our teacher told us but I can't seem to get it.
  2. jcsd
  3. Nov 7, 2007 #2


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    I'd try to convert all the terms to cos(x), then set y = cos(x), then use the quadratic formula.
  4. Nov 7, 2007 #3
    thanks I got 1/2 and -1 for the roots with that then set that equal to cos(x) to find the roots of the actual problem ?
    Last edited: Nov 7, 2007
  5. Nov 7, 2007 #4
    is this your problem?


    you have sin^x ... idk how to interpret that
  6. Nov 8, 2007 #5


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    Or is it

    [tex]\cos^{2}{x}-\sin^{2}{x}+\cos{x}[/tex] ??
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