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Homework Help: Determine curve

  1. Feb 12, 2008 #1
    1. The problem statement, all variables and given/known data

    Determine whether the curve x = 3t^2, y = e^2t+1 is concave up or concave down at the point (3, e^3)

    thanks for any help with this one.

    2. Relevant equations

    3. The attempt at a solution

    know i need to take the double derivative. Also that would be 6
    and 4e^2t+1

    what point do i put back into the double derivative. Also, do I use 3 and e^3? they represent x, y, so do they plug into the equation appropriately, or back into t? please help.
  2. jcsd
  3. Feb 12, 2008 #2


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    Science Advisor
    Homework Helper
    Gold Member

    If you know how to determine concavity or concavity when given a function y(x), then I suggest you try to "eliminate" that nasty t and try to write y as a function of x!
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