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Chain Rule Help

  1. Sep 26, 2007 #1
    1. The problem statement, all variables and given/known data

    g(t) = 4ln(5ln(4t))

    2. Relevant equations

    What is the derivative of g(t)?

    3. The attempt at a solution

    I have tried to use the chain rule in many different ways, and still can't come up with the correct answer. Anybody care to walk me through this? Is the derivative of ln(4t) still 1/t?
  2. jcsd
  3. Sep 26, 2007 #2


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    (ln(4t))'=(1/(4t))*4=1/t. Yes. It's still 1/t. For your problem g'=4*(1/(5*ln(4t)) times the derivative of 5*ln(4t). What do you make it?
  4. Sep 26, 2007 #3
    4*(1/(5*ln(4t)) = 4/(5*ln(4t))
    Deriv 5*ln(4t) = 5/t

    5/t * 4/(5*ln(4t)) = 20/(5t*ln(4t)) = 4/(t*ln(4t)) =

  5. Sep 26, 2007 #4


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    I agree with that.
  6. Sep 26, 2007 #5
    So does the answer key. Thanks for your help.
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