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Homework Help: 1st and 2nd Derivative

  1. Apr 23, 2009 #1
    1. The problem statement, all variables and given/known data
    If x = cos(3t) and y = (sin(3t))² find dy/dx and d²y/dx².

    2. Relevant equations
    d/dx cosx = -sinx
    d/dx sinx = cosx

    3. The attempt at a solution
    dx/dt = -3sin3t
    dy/dt = 6sin3tcos3t

    Not sure what to do now.
  2. jcsd
  3. Apr 23, 2009 #2


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    (dy/dt)/(dx/dt)=dy/dx, right?
  4. Apr 23, 2009 #3
    Yes, thank you. After I posted I wondered whether you could do that or not (a little unfamiliar with Leibniz notation) but it makes sense now thank you.
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