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Limit of ln as x goes to infinity

  1. Mar 7, 2012 #1
    1. The problem statement, all variables and given/known data
    lim (lnx)^2/x
    x-->infinity


    2. Relevant equations

    none

    3. The attempt at a solution

    =5lnx/x * (1/lnx)/(1/lnx)

    =5/(x/lnx)

    How do I calculate x/lnx?
     
  2. jcsd
  3. Mar 7, 2012 #2

    ehild

    User Avatar
    Homework Helper
    Gold Member

    I do not follow you. What have you done?

    ehild
     
  4. Mar 7, 2012 #3

    Mark44

    Staff: Mentor

    Where did the 5 come from? In fact, where did any of this come from? What you have makes zero sense to me.

    Also, since you haven't taken the limit yet, you should not get rid of the "lim" symbol.
    This is a problem that is suited to L'Hopital's Rule. Have you covered it yet?
     
  5. Mar 8, 2012 #4
    Cacophony,

    what you typed is equivalent to:

    [tex]\displaystyle \lim_{x\to \infty}\dfrac{[ln(x)]^2}{x}[/tex]



    Did you intend

    [tex]\displaystyle \lim_{x\to \infty}[ln(x)]^{\frac{2}{x}} \ ?[/tex]
     
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