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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

    Mark44

    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.
     
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