1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    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


    User Avatar
    Homework Helper

    I believe for that equation to work 'a' must be a constant.
  6. Dec 1, 2008 #5
    O, thanks.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook