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

In summary, the limit of (-1)^n * n/(n+1) as n approaches infinity oscillates between -1 and 1. One way to show this analytically is by dividing the numerator and denominator of the fraction by n and observing the behavior as n approaches infinity. Using LaTeX, the limit can be written as \lim_{n\rightarrow \infty}.
  • #1
Bashyboy
1,421
5

Homework Statement


[itex]\stackrel{lim}{n\rightarrow \infty} (-1)^n \frac{n}{n + 1}[/itex]


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.
 
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  • #2
Bashyboy said:

Homework Statement


[itex]\stackrel{lim}{n\rightarrow \infty} (-1)^n \frac{n}{n + 1}[/itex]


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##?
 
  • #3
Ah, yes, I see. Thank you.
 
  • #4
Writing limits in LaTeX looks better with the following code:

Code:
\lim_{n\rightarrow \infty}

There is no need for stackrel and such.
 

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

What is a sequence?

A sequence is a list of numbers in a specific order. In mathematics, sequences can be finite (with a defined number of terms) or infinite (with an endless number of terms). Each term in a sequence can be represented by a specific rule or pattern.

What is a limit of a sequence?

A limit of a sequence is the value that the sequence approaches as the number of terms increases. It is the value that the terms in the sequence get closer and closer to, but never actually reach.

How can I solve a limit of a sequence?

To solve a limit of a sequence, you can use the formula for the general term (or nth term) of the sequence and plug in increasing values for n. As n gets larger and larger, the terms of the sequence will get closer to the limit value. You can also use algebraic techniques, such as factoring or simplifying, to solve limits of sequences.

What is the specific sequence (-1)^n \frac{n}{n + 1}?

This sequence alternates between positive and negative values, with the magnitude of the terms getting closer to 1 as n increases. It is a geometric sequence with a common ratio of -1 and a general term of (-1)^n \frac{n}{n + 1}.

What is the limit of the sequence (-1)^n \frac{n}{n + 1}?

The limit of this sequence is 1, as n approaches infinity. This can be determined by plugging in larger and larger values for n, which will result in the absolute value of the terms getting closer and closer to 1. This can also be proven mathematically using algebraic techniques.

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