Chapter 10: Problem 53
Which of the sequences \(\left\\{a_{n}\right\\}\) converge, and which diverge? Find the limit of each convergent sequence. \(a_{n}=\left(1+\frac{7}{n}\right)^{n}\)
Short Answer
Expert verified
The sequence converges to \( e^7 \).
Step by step solution
01
Identifying the Sequence Type
The sequence given is \( a_n = \left(1+\frac{7}{n}\right)^n \), which is of the form that resembles the expression for Euler’s number \( e \) as \( n \to \infty \). This suggests it might converge to a limit involving \( e \).
02
Expressing the Sequence in Terms of Exponential Function
The term \( \left(1+\frac{7}{n}\right)^n \) can be linked to the exponential function. As \( n \to \infty \), \( \left(1+\frac{x}{n}\right)^n \to e^{x} \). Therefore, by setting \( x = 7 \), this sequence converges to \( e^{7} \).
03
Confirming Convergence
Since \( \left(1+\frac{7}{n}\right)^n \to e^7 \) as \( n \to \infty \), the sequence is indeed convergent. The convergence is supported by the definition of the limit for exponential sequences as \( n \to \infty \).
04
Finding the Limit
The limit of the sequence \( a_n = \left(1+\frac{7}{n}\right)^n \) as \( n \to \infty \) is \( e^7 \). Thus, the sequence is convergent with limit \( e^7 \).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Euler's number
Euler's number, denoted as \( e \), is a fundamental mathematical constant. It is approximately equal to 2.71828. The number is named after the Swiss mathematician Leonhard Euler, who made many contributions to the field.
\( e \) is widely known for its role in the exponential function \( e^x \), and it naturally arises in various mathematical contexts. For example:
\( e \) is widely known for its role in the exponential function \( e^x \), and it naturally arises in various mathematical contexts. For example:
- It is the base rate of growth shared by all continually growing processes.
- It appears in natural logarithms as the inverse function of the exponential function.
- Euler's number is crucial in calculus and complex analysis, particularly when solving differential equations.
Limit Evaluation
Limit evaluation is a key concept in calculus, helping to determine the behavior of functions as they approach a specific point. It's essential when discussing the convergence of sequences.
To evaluate the limit of a sequence \( a_n \) as \( n \to \infty \), we examine how the sequence behaves as the variable \( n \), typically an integer, increases without bound. Here's a breakdown of the process:
To evaluate the limit of a sequence \( a_n \) as \( n \to \infty \), we examine how the sequence behaves as the variable \( n \), typically an integer, increases without bound. Here's a breakdown of the process:
- **Identify the form of the sequence:** Recognize patterns that resemble known limits, such as the form \((1 + \frac{x}{n})^n\).
- **Use known limit properties:** For instance, the limit \((1 + \frac{x}{n})^n \to e^x\) as \( n \to \infty \) is crucial for our given sequence \( (1 + \frac{7}{n})^n \).
- **Confirm convergence:** Once the form resembles a known limit, confirm it with calculus principles, ensuring the sequence approaches a specific value, indicating convergence.
Exponential Function
The exponential function, denoted \( e^x \), is one of the most important functions in mathematics. It features the base \( e \), Euler's number, and displays unique properties:
- **Undefined slope at 0:** The derivative of \( e^x \) at any point is itself, \( e^x \), exemplifying its rapid growth.
- **Growth and decay:** \( e^x \) describes growth processes, while \( e^{-x} \) handles decay, vital in fields such as physics and economics.
- **Natural Logarithms:** This inverse relationship makes the exponential function fundamental in solving logarithmic equations.