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Critical Points

  1. Feb 2, 2013 #1
    for cos y the critical points are n*pi - 0.5*pi
    for cos 2x, the critical points should be n/2 * pi - 0.25*pi
    because if I set y=2x = n*pi - 0.5*pi , I get the eq in red for x.
    However if I do it graphically, I just get n*pi - 0.25*pi.
    The question: why algebraically I am constrained to use the even number n but graphically, there is no restriction on n?
  2. jcsd
  3. Feb 2, 2013 #2


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    2017 Award

    Staff: Mentor

    I think your critical points for cos y are wrong. Do you mean sin?

    Answer: At least one of them is wrong.
  4. Feb 2, 2013 #3


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    Science Advisor

    I think you have critical point and root mixed up.
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