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!

Help with derivatives of natural logs

  1. Oct 15, 2009 #1
    1. The problem statement, all variables and given/known data

    (ln(1+e^x))^6

    2. Relevant equations



    3. The attempt at a solution
    Honestly I haven't done this in 3 years and a friend asked me to help them with it. I'm at a bit of loss.
     
  2. jcsd
  3. Oct 15, 2009 #2

    Mark44

    Staff: Mentor

    I'll help you with one of the steps.
    d/dx[ (ln(1+ex))6] = 6(ln(1 + ex)5* d/dx(ln(1 + ex))

    Is that enough of a start?
     
  4. Oct 15, 2009 #3
    I'll pass it on to her and find out. Thanks.
     
  5. Oct 15, 2009 #4
    There's a difference between (ln(1+ex))6 and ln(1+ex)6 = ln[(1+ex)6]
    The ln has the exponent, not the argument of the ln, so you can't pull the exponent out in front.
     
  6. Oct 16, 2009 #5

    Mark44

    Staff: Mentor

    I understand that there is a difference.

    The problem as posted is
    As you can see, it was NOT ln(1 + ex)6, as you seem to think.
    Because the log expression is raised to the 6th power, the derivative is 6( ln(1 + ex))5 * d/dx(ln(1 + ex)).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Help with derivatives of natural logs
Loading...