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Homework Help: What's Wrong With My Answer?

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

    y = (3x)^x

    (find y' )

    2. Relevant equations

    y = a^x
    y' = (a^x)(ln(a))

    and the chain rule

    3. The attempt at a solution

  2. jcsd
  3. Dec 1, 2008 #2


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    Homework Helper

    Take ln of both sides of the equation


    Now use implicit differentiation
  4. Dec 1, 2008 #3
    yes, that was the answer that was provided; but I don't understand why my answer is incorrect, given the fact that the derivative of a^x is (a^x)(lin(a)) and the formula seems to be of that form.
  5. Dec 1, 2008 #4


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    Homework Helper

    I believe for that equation to work 'a' must be a constant.
  6. Dec 1, 2008 #5
    O, thanks.
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