/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 40 Find the limits. $$\lim _{x \r... [FREE SOLUTION] | 91Ó°ÊÓ

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Find the limits. $$\lim _{x \rightarrow 0^{+}}\left(e^{2 x}-1\right)^{x}$$

Short Answer

Expert verified
The limit is 1.

Step by step solution

01

Identify the Expression to Simplify

The limit involves the expression \( (e^{2x} - 1)^x \). As \( x \rightarrow 0^{+} \), both \( e^{2x} - 1 \rightarrow 0 \) and \( x \rightarrow 0 \). This forms an indeterminate type \( 0^0 \). We need to simplify the expression in order to evaluate this limit.
02

Use Logarithmic Properties

To handle the indeterminate form, take the natural logarithm of the expression: \( \ln(y) = x \cdot \ln(e^{2x} - 1) \), where \( y = (e^{2x} - 1)^x \). This will help simplify the evaluation process.
03

Simplify the Inner Logarithm

Approximate \( e^{2x} - 1 \) using the Taylor expansion: \( e^{2x} \approx 1 + 2x + (2x)^2/2! + \ldots \). So, \( e^{2x} - 1 \approx 2x \). Therefore, \( \ln(e^{2x} - 1) \approx \ln(2x) \).
04

Calculate the Limit of the Logarithmic Expression

Substitute \( \ln(e^{2x} - 1) \approx \ln(2x) \) into the expression: \( \ln(y) = x \cdot \ln(2x) = x(\ln 2 + \ln x) = x \ln 2 + x \ln x \). Evaluate the limit: \( \lim_{x \rightarrow 0^{+}} (x \ln 2 + x \ln x) \).
05

Simplify \(x \ln x\) and Evaluate

Use the identity: \( \lim_{x \rightarrow 0^{+}} x \ln x = 0 \). Thus, the expression simplifies as \( \lim_{x \rightarrow 0^{+}} x \ln 2 + \lim_{x \rightarrow 0^{+}} x \ln x = 0 \).
06

Evaluate the Original Limit

Since \( \ln(y) \rightarrow 0 \), we conclude that \( y \rightarrow e^{0} = 1 \). Therefore, the limit is \( 1 \).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Indeterminate Forms
When evaluating limits in calculus, we often encounter expressions that are not immediately clear to solve. These expressions are called indeterminate forms. One such indeterminate form is \(0^0\). In the given exercise, as \(x\) approaches 0 from the positive side, both \(e^{2x} - 1\) and \(x\) tend toward zero, creating the indeterminate form \(0^0\). Indeterminate forms like \(0^0\) require special techniques to evaluate. Simply plugging in numbers won't work because the result isn't clearly defined. Mathematicians have devised strategies, like taking logarithms or using L'Hôpital's Rule, to resolve these cases. In the solution, taking the natural logarithm of the entire expression transforms the problem into a more manageable form. Becoming familiar with various indeterminate forms is crucial in calculus, as it allows you to strategically choose methods to find limits effectively.
Logarithmic Properties
Logarithms play a pivotal role in simplifying expressions involving limits, especially when dealing with exponents. In this exercise, the expression \((e^{2x} - 1)^x\) can be made more approachable by taking its natural logarithm.By applying this property, we convert the power expression into a product: \(\ln(y) = x \cdot \ln(e^{2x} - 1)\). This transformation is essential as multiplications are often easier to handle in limit evaluations than exponentials.The natural logarithm also helps break down complex expressions. Once we simplify the expression inside the logarithm, such as using a Taylor expansion, it becomes feasible to evaluate the limit of the resulting simpler terms. Understanding how logs can convert and simplify expressions is a powerful tool in calculus, especially for limit problems.
Taylor Expansion
A Taylor expansion is a mathematical tool that approximates functions with polynomials. This is especially useful when dealing with exponential functions and evaluating limits. For small values of \(x\), the exponential function \(e^{2x}\) can be approximated by its Taylor series expansion:\[ e^{2x} \approx 1 + 2x + \frac{(2x)^2}{2!} + \ldots \]In the exercise, \(e^{2x} - 1\) is approximated using the Taylor expansion. Since the higher-order terms become insignificant as \(x\) approaches zero, this approximates to \(2x\). This simplification allows the initial complex expression to be transformed into a simpler form.The Taylor expansion is invaluable for breaking down complex functions into more accessible polynomial forms. It enables the near-exact approximation of functions at points of interest, often making the difference between an intractable and an easily solvable problem. Understanding and applying Taylor expansions is fundamental for anyone delving into the deeper aspects of calculus.

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