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Homework Help: F''(x) Second Derivative problem

  1. Nov 23, 2008 #1
    1. The problem statement, all variables and given/known data
    find f''(x) <-- second derivative
    f(x) = 3e^-x2 <-- that 2 is x squared

    2. Relevant equations

    3. The attempt at a solution
    my attempt was 6x^2 e^x2
  2. jcsd
  3. Nov 23, 2008 #2


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    Try taking the first derivative first, then take the second derivative.
  4. Nov 23, 2008 #3

    On the right track, but you're not quite remember your rules correctly.

    For the first derivative, use the chain rule. Derivative of the outside 3e^(x^2) times the derivative of the inside (x^2)

    Once you've got that, you're going to have a function that is an x times an exponential along the lines of ?xe^(x^2). From there, you need to use the product rule. Which is the derivative of the first function (?x) times the second function (e^(x^2)) plus the first function times the derivative of the second function. Or f'(x)g(x)+f(x)g'(x) (should be familiar from your text) On the derivative of your second function, don't forget the chain rule again!

    Hopefully that helps, or if not, that someone can come and correct me.
  5. Nov 23, 2008 #4
    thanks that helped a bunch i think i got it.
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