Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Show that n^(logc)/c^(logn) =1 as n->inf

  1. Jan 31, 2012 #1
    1. The problem statement, all variables and given/known data
    Show that n^(logc)/c^(logn) =1 as n->inf where c is a constant greater than 1

    2. Relevant equations

    3. The attempt at a solution

    Tried L'hospitals. But the logs mess it up. Even if you assume that logc>1 then the top does eventually become a constant (second derivative). However the bottom gets too messy. Is there another method to start it?
  2. jcsd
  3. Jan 31, 2012 #2

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    If f(n) = n^log(c) / c^log(n), look carefully at log (f(n)).

  4. Jan 31, 2012 #3
    Thats log(n^logc/c^logn)= log(n^logc)-log(c^logn)=log(c)log(n)-log(n)log(c)=0.

    Ok i got it

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook