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: L'hopital's Rule for solving limit problem

  1. Nov 23, 2008 #1
    The question is:
    Evaluate the following limit: lim(as x tends to 1) of [(x-1)^3]/(logx)

    I tried using L'hopital's Rule, so i differentiated the top and bottom of the eqn and i got 3x(x-1)^2, then as x tends to 1 this would tend to 0.

    I don't think this is correct though, and was wondering if anyone could give me some guide lines to maybe another rule to use to find the limit.

  2. jcsd
  3. Nov 23, 2008 #2
    Re: Limits

    Why would you think so? It's perfectly correct, well done.
  4. Nov 23, 2008 #3
    Re: Limits

    But to use l'hopital's rule, dont you need the limit, x, tending to zero?
  5. Nov 23, 2008 #4
    Re: Limits

    No, you only need both the numerator and the denumerator tend to zero (or infinity) as x approaches some number a, for example one.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook