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: Complicated derivative problem

  1. Mar 12, 2009 #1
    d/du [((u(n+1))/(n+1)2) ((n+1) ln(u) - 1)]

    how would you take the derivative of this large complicated function?
  2. jcsd
  3. Mar 12, 2009 #2


    Staff: Mentor

    First, bring out the factor of 1/(n + 1)^2, since it doesn't depend on u. Then use the product rule on u^(n+1)*((n + 1) ln(u) - 1)
  4. Mar 29, 2009 #3
    so would "n" be a constant in this problem? i took the derivative and i got something like this:

    (u(n+1)(n+1)(ln u))(n+1)(lnu - 1) + (u(n+1))(n+1)(1/u)

    all of that over (n+1)2. is this right?
  5. Mar 30, 2009 #4
    you still need to decrement the power after differentiation. all of this simplifies considerably.
    [edit] you shouldn't have two (ln u) terms.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook