# Understanding the Limit of (1 + 1/n)^n as n Approaches Infinity

September 28, 2023
USA
Math
Jonathan Bradwell has a master’s in mathematics and is an accomplished assignment writer. He has over 700 clients.

Mathematics assignments can sometimes present challenging problems that require a deep understanding of fundamental concepts. In this blog, we will embark on a theoretical journey to solve a classic mathematical problem that often appears in university assignments: determining the limit of the expression (1 + 1/n)^n as n approaches infinity. We will provide a step-by-step theoretical explanation of this limit, helping university students grasp the underlying concepts and seek assistance with their math assignment effectively.

## The Problem Statement:

solve your math assignment effectively, it is essential to comprehend the concept of limits and how they apply to various mathematical expressions. The problem at hand is to find the limit of the expression (1 + 1/n)^n as n tends to infinity. This involves understanding the behavior of the expression as n becomes increasingly larger.

## Understanding the Limit Concept:

Before delving into the solution, let's briefly revisit the concept of limits in mathematics. A limit represents the value that a function or sequence approaches as its input (in this case, n) approaches a specific value (in this case, infinity). The formal definition of a limit involves ensuring that for any given positive number ε (epsilon), there exists a positive number δ (delta) such that if the input is within δ units of the limit value, the function's output is within ε units of the limit value.

In our case, we want to find the limit of (1 + 1/n)^n as n approaches infinity. To do this, we need to demonstrate that as n becomes larger and larger, the expression approaches a specific value.

### Step 1: Rewriting the Expression

To begin, let's rewrite the expression (1 + 1/n)^n to facilitate our theoretical analysis. We will use algebraic manipulation to simplify it:

(1 + 1/n)^n = [(n/n) + (1/n)]^n = [(n+1)/n]^n

Now, we have the expression [(n+1)/n]^n to work with.

### Step 2: Applying the Limit Definition

To find the limit of [(n+1)/n]^n as n approaches infinity, we will use the limit definition mentioned earlier. We want to show that as n grows without bound, this expression approaches a particular value.

Let L denote the limit we are trying to find:

L = lim (n → ∞) [(n+1)/n]^n

### Step 3: Using Indeterminate Form

The limit L appears to be in an indeterminate form (∞/∞), which means we can apply L'Hôpital's Rule. This rule is a powerful tool for finding the limits of indeterminate forms by taking derivatives.

### Step 4: Applying L'Hôpital's Rule

To use L'Hôpital's Rule, we differentiate the numerator and denominator with respect to n:

L = lim (n → ∞) [(n+1)/n]^n

= lim (n → ∞) [d/dn(n+1)/d/dn(n)] // Differentiating numerator and denominator

= lim (n → ∞) [(1/n)/(1)] // Simplifying the derivatives

= lim (n → ∞) (1/n) // Simplifying further

### Step 5: Taking the Limit

Now, we have reduced the expression to lim (n → ∞) (1/n), which is a simpler limit problem.

## Exploring the Behavior of (1 + 1/n)^n as n Approaches Infinity: A Theoretical Journey

In our previous discussion, we demonstrated that the limit of the expression (1 + 1/n)^n as n approaches infinity is 0. Now, let's dive deeper into the intuition behind this result and explore some practical examples of how this mathematical concept applies in various fields.

### Understanding the Intuition:

The limit we just solved, lim (n → ∞) (1/n), provides us with valuable insight into the behavior of the expression (1 + 1/n)^n as n becomes increasingly large. The result, 0, indicates that as n approaches infinity, the value of the expression gets closer and closer to zero. But why does this happen?

### Concept of Continuity:

To understand this, we need to introduce the concept of continuity. In mathematics, a function is considered continuous at a particular point if the value of the function at that point is equal to the limit of the function as it approaches that point. In our case, we're interested in the continuity of the function f(x) = (1 + 1/x)^x as x approaches infinity.

### Euler's Number:

Here's where Euler's number, denoted as 'e,' comes into play. Euler's number is approximately equal to 2.71828 and plays a fundamental role in various mathematical contexts, including calculus and exponential growth. It is often defined as the limit:

e = lim (n → ∞) (1 + 1/n)^n

This definition resembles our original problem, and indeed, as n approaches infinity, (1 + 1/n)^n approaches 'e.' This is one of the key properties of 'e' and demonstrates its significance in mathematics.

### Application in Compounded Interest:

Understanding limits and exponential functions is not just a theoretical exercise; it has practical applications in fields like finance. Consider the concept of compounded interest. When interest is compounded continuously, we use the formula:

A = P * e^(rt)

Where:

• A is the final amount
• P is the principal amount
• r is the annual interest rate
• t is the time (in years)
• e is Euler's number

In this formula, the continuous compounding of interest is modeled using 'e.' It shows how an investment grows when interest is continually added to the principal amount. Understanding the limit definition of 'e' helps financial professionals calculate the growth of investments more accurately.

### Application in Probability:

The limit (1 + 1/n)^n also finds application in probability theory. It is intimately linked to the concept of probability distributions and the famous Euler's constant 'γ,' also known as the Euler-Mascheroni constant. This constant is defined as:

γ = lim (n → ∞) [1 + 1/2 + 1/3 + ... + 1/n - ln(n)]

Here, the limit resembles our original problem, and it plays a crucial role in the study of probability distributions, particularly the harmonic series. Understanding this limit is essential for comprehending the behavior of certain probability distributions, which is vital in fields such as statistics and actuarial science.

### Application in Calculus:

In calculus, understanding limits is fundamental to grasping the concept of differentiation and integration. Limits help us determine slopes of tangent lines, rates of change, and areas under curves. The expression (1 + 1/n)^n is closely related to the definition of the exponential function e^x, which is one of the most important functions in calculus.

The derivative of e^x is itself, which is an extraordinary property. The limit we discussed earlier is intricately tied to this derivative, making it a cornerstone of calculus. It allows us to understand the behavior of exponential functions, their growth rates, and how they behave under various transformations.

## Connecting to Other Mathematical Concepts:

Our journey into understanding the limit of (1 + 1/n)^n has already led us to Euler's number 'e' and the concept of continuity. However, this limit also has intriguing connections to other mathematical topics, such as sequences and series.

### 1. Sequences and Series:

As n approaches infinity, we are effectively dealing with an infinite sequence of numbers: (1 + 1/n)^n for n = 1, 2, 3, ... The study of sequences and series is essential in calculus and mathematical analysis.

The expression (1 + 1/n)^n represents a sequence of values, and we are interested in its limit as n extends infinitely. This sequence is known as the "sequence of powers of e." Each term of this sequence gets closer and closer to 'e' as n grows larger, which is a remarkable property of 'e' and the reason why it is often called the "limiting value."

### 2. Taylor Series:

The Taylor series is a powerful tool in calculus that allows us to represent a wide range of functions as infinite series of terms. Understanding the limit of (1 + 1/n)^n plays a crucial role in the Taylor series expansion of the exponential function e^x. The Taylor series for e^x is given by:

e^x = 1 + x + (x^2/2!) + (x^3/3!) + (x^4/4!) + ...

This series reveals a deep connection between the expression (1 + 1/n)^n and the exponential function e^x. As n approaches infinity in (1 + 1/n)^n, we see the emergence of the terms 1, x, x^2/2!, x^3/3!, and so on, which are integral to the Taylor series for e^x. Thus, understanding limits helps us unlock the expansion of complex functions into simpler components.

### 3. Riemann Sum and Definite Integrals:

In calculus, the definite integral represents the "area under the curve" of a function over a specific interval. The Riemann sum is a crucial concept in understanding definite integrals. When we calculate definite integrals, we often use limits to approximate the area under the curve by dividing it into smaller and smaller pieces.

The limit of (1 + 1/n)^n is closely tied to the calculation of definite integrals. As n increases, the expression converges to 'e,' and this behavior is analogous to taking finer and finer partitions when approximating the area under a curve using Riemann sums. This connection between limits and integrals is essential for understanding the fundamental theorem of calculus.

## Applications Beyond Mathematics:

While the limit of (1 + 1/n)^n may seem like an abstract mathematical concept, its applications extend far beyond the realm of mathematics itself.

### 1. Biology:

In the field of biology, this limit has been used to model population growth and predict the limit of a population as it undergoes continuous changes. Understanding the concept of limits is crucial for studying how populations evolve over time, considering factors such as birth rates, death rates, and immigration.

### 2. Physics:

In physics, the behavior of particles in quantum mechanics can be described using wave functions. The limit of (1 + 1/n)^n plays a role in understanding the probability distribution of particles in a quantum system, shedding light on the wave-particle duality and the probabilistic nature of quantum phenomena.

### 3. Economics:

Economists use mathematical models to analyze economic trends, and the concept of limits is integral to understanding how variables like interest rates, inflation, and economic growth behave over time. Limits play a role in predicting economic equilibrium and studying dynamic economic systems.

## The Fundamental Nature of Limits:

To fully appreciate the importance of understanding limits, it's crucial to acknowledge their fundamental nature in mathematics. Limits are at the heart of calculus, which is often referred to as the mathematics of change. Calculus helps us analyze how quantities change with respect to one another, making it a foundational tool in fields ranging from physics to engineering.

### 1. Applications in Rates of Change:

Calculus provides a framework for studying rates of change, and limits are the essential building blocks of this framework. When we calculate derivatives, which represent rates of change, we are essentially evaluating limits. For example, when determining the instantaneous velocity of an object or the slope of a tangent line to a curve, we use limits. Understanding the limit of (1 + 1/n)^n is a stepping stone to grasping these advanced concepts.

### 2. Connection to the Fundamental Theorem of Calculus:

The Fundamental Theorem of Calculus is a central result that links the two main branches of calculus: differentiation and integration. It states that if you have a continuous function f(x) and you find its antiderivative, denoted as F(x), then the definite integral of f(x) from 'a' to 'b' is equal to F(b) - F(a). Limits play a crucial role in proving and understanding this theorem. The limit of (1 + 1/n)^n serves as a fundamental example of how limits are used to define exponential functions, which are essential in integration techniques.