Solving Limits of Sequences: (-1)^n \frac{n}{n + 1}

  • Thread starter Thread starter Bashyboy
  • Start date Start date
  • Tags Tags
    Limits Sequences
Bashyboy
Messages
1,419
Reaction score
5

Homework Statement


\stackrel{lim}{n\rightarrow \infty} (-1)^n \frac{n}{n + 1}


Homework Equations





The Attempt at a Solution


The answer is that the limit oscillates between -1 and 1, but I was wondering if there was an analytic was of showing this.
 
Physics news on Phys.org
Bashyboy said:

Homework Statement


\stackrel{lim}{n\rightarrow \infty} (-1)^n \frac{n}{n + 1}


Homework Equations





The Attempt at a Solution


The answer is that the limit oscillates between -1 and 1, but I was wondering if there was an analytic was of showing this.


Well, you know the sign alternates. What happens if you divide the numerator and denominator of your fraction by n? What happens then as ##n\to\infty##?
 
Ah, yes, I see. Thank you.
 
Writing limits in LaTeX looks better with the following code:

Code:
\lim_{n\rightarrow \infty}

There is no need for stackrel and such.
 
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...

Similar threads

Back
Top