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

  • Thread starter Thread starter bfpri
  • Start date Start date
bfpri
Messages
11
Reaction score
0

Homework Statement


Show that n^(logc)/c^(logn) =1 as n->inf where c is a constant greater than 1

Homework Equations


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?
 
Physics news on Phys.org
If f(n) = n^log(c) / c^log(n), look carefully at log (f(n)).

RGV
 
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

Thanks
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top