Limit Function: Finding Solution

In summary, the limit of the given function can be found by simplifying it and using properties of limits and exponents. It can also be solved using L'Hospital's Rule or by recognizing the limit as a special case of the limit of $(1+\frac{x}{n})^n$. The final result is that the limit is equal to 0.
  • #1
tmt1
234
0
I'm trying to find the limit of this function:

$$\lim_{{n}\to{\infty}} \frac{n^n}{({n + 1})^{n + 1}}$$

I can simplify it to this:

$$\lim_{{n}\to{\infty}} \frac{n^n}{({n + 1})^{n}(n + 1)}$$

But I'm not sure of the best way to proceed.
 
Physics news on Phys.org
  • #2
tmt said:
I'm trying to find the limit of this function:

$$\lim_{{n}\to{\infty}} \frac{n^n}{({n + 1})^{n + 1}}$$

I can simplify it to this:

$$\lim_{{n}\to{\infty}} \frac{n^n}{({n + 1})^{n}(n + 1)}$$

But I'm not sure of the best way to proceed.

$\displaystyle \begin{align*} &= \lim_{n \to \infty} \left( \frac{n}{n + 1} \right) ^n \left( \frac{1}{n + 1} \right) \\ &= \lim_{n \to \infty} \left( \frac{n}{n + 1} \right) ^n \, \lim_{n \to \infty} \frac{1}{n + 1} \\ &= \lim_{n \to \infty} \left( 1 - \frac{1}{n + 1} \right) ^n \,\lim_{n \to \infty} \frac{1}{n + 1} \\ &= \lim_{n \to \infty} \mathrm{e}^{ \ln{ \left[ \left( 1 - \frac{1}{n + 1} \right) ^n \right] } }\,\lim_{n \to \infty} \frac{1}{n + 1} \\ &= \mathrm{e}^{ \lim_{n \to \infty} \frac{\ln{ \left( 1 - \frac{1}{n + 1} \right) }}{\frac{1}{n}} }\,\lim_{n \to \infty} \frac{1}{n + 1} \end{align*}$

Use L'Hospital's Rule to finish it off :)
 
  • #3
An alternative to L'Hospital's rule in this context is the fact that $\lim_{n\to\infty}\left(1+\frac{x}{n}\right)^n=e^x$. Then
\begin{align}
\lim_{n\to\infty}\left(1-\frac{1}{n+1}\right)^n&=
\lim_{n\to\infty}\left(1-\frac{1}{n+1}\right)^{n+1}\left(\frac{n+1}{n}\right)\\
&=\lim_{n\to\infty}\left(1-\frac{1}{n}\right)^{n}\lim_{n\to\infty}\left(\frac{n+1}{n}\right)\\
&=e^{-1}\cdot1.
\end{align}
 
  • #4
Alternatively:
$$\frac{n^n}{({n + 1})^{n + 1}} = \left(\frac{n}{n + 1}\right)^{n} \cdot \frac{1}{n + 1} \le 1^n \cdot \frac{1}{n + 1} \to 0
$$
So:
$$\lim_{{n}\to{\infty}} \frac{n^n}{({n + 1})^{n + 1}} = 0$$
 

FAQ: Limit Function: Finding Solution

What is a limit function?

A limit function is a mathematical concept that describes the behavior of a function as its input approaches a specific value. It is used to determine the value that a function approaches as its input gets closer and closer to a particular value.

How do you find the limit of a function?

To find the limit of a function, you can use various methods such as direct substitution, factoring, or rationalization. You can also use graphs or tables to estimate the limit. In some cases, you may need to use more advanced techniques such as L'Hôpital's rule or the squeeze theorem.

What is the importance of finding the limit of a function?

Finding the limit of a function is crucial in many areas of mathematics and science. It helps in understanding the behavior of a function and its properties, such as continuity and differentiability. It also has practical applications in fields such as physics, engineering, and economics.

What are the common types of limits?

The most common types of limits are one-sided limits, where the input approaches the specified value from one direction, and two-sided limits, where the input approaches the value from both directions. Other types of limits include infinite limits, where the function grows without bound, and limits at infinity, where the input approaches a very large value.

Can a limit function have multiple solutions?

No, a limit function can only have one solution. The limit represents the value that the function approaches as the input gets closer to a specific value, and this value is unique. However, a function can have different limits at different points, leading to a discontinuity in the function.

Similar threads

Back
Top