/*! 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 43 Determine the infinite limit. ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Determine the infinite limit. $$ \lim _{x \rightarrow 0}\left(\ln x^{2}-x^{-2}\right) $$

Short Answer

Expert verified
The limit is \(-\infty\).

Step by step solution

01

Analyze the Components of the Function

Given function is \( f(x) = \ln(x^2) - x^{-2} \). This simplifies to \( f(x) = 2\ln|x| - \frac{1}{x^2} \). As \( x \to 0 \), both components need separate analysis.
02

Analyze \( \ln(x^2) \)

As \( x \to 0^+ \), \( x^2 \to 0^+ \) and \( \ln(x^2) \to -\infty \). Similarly, as \( x \to 0^- \), \( x^2 \to 0^+ \) and \( \ln(x^2) \to -\infty \). Thus, \( 2\ln|x| \to -\infty \) as \( x \to 0 \).
03

Analyze \( x^{-2} \)

As \( x \to 0^+ \), \( x^{-2} \to +\infty \). Similarly, as \( x \to 0^- \), \( x^{-2} \to +\infty \). Hence, \( -x^{-2} \to -\infty \) as \( x \to 0 \).
04

Combine the Limits

Since \( 2\ln|x| \to -\infty \) and \( -\frac{1}{x^2} \to -\infty \), combining these gives \( 2\ln|x| - \frac{1}{x^2} \to -\infty - \infty = -\infty \).
05

Conclusion

The limit of the function as \( x \rightarrow 0 \) is \(-\infty\). Therefore, \( \lim _{x \rightarrow 0}(\ln x^{2}-x^{-2}) = -\infty \).

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Key Concepts

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

Infinite Limits
Infinite limits occur when a function approaches an infinitely large positive or negative value as the input gets closer to a particular point. In the context of the exercise, we're examining what happens to the function \( f(x) = 2\ln|x| - \frac{1}{x^2} \) as \( x \) approaches zero. This involves considering the behavior of the natural logarithm and the reciprocal squared function.When approaching zero, the term \( \frac{1}{x^2} \) zooms towards infinity since the denominator becomes exceedingly small. Consequently, \( -\frac{1}{x^2} \) tends to negative infinity. Meanwhile, \( 2\ln|x| \) also heads towards negative infinity as \( x \) nears zero. Combined, these behaviors mean that the overall function races towards \(-\infty\), illustrating an infinite limit.
Natural Logarithm
The natural logarithm, denoted as \( \ln(x) \), is a special type of logarithm that uses the base \( e \), approximately equal to 2.718. The function is only defined for positive values of \( x \), and it is crucial for understanding certain limits, including infinite limits, as shown in the exercise.Properties of Natural Logarithm:
  • \( \ln(1) = 0 \): The value of ln at 1 is always zero.
  • \( \ln(x)\) becomes negative as \( x \) approaches zero from the positive side.
  • \( \ln(x) \) tends towards infinity as \( x \) increases indefinitely.
In the problem, \( 2\ln|x| \), with \( |x|^2 = x^2 \), tends towards \(-\infty\) as \( x \to 0 \). This is because the square of a small number approaches zero, and thus its logarithm approaches negative infinity.
Limit Analysis
Limit analysis is the method of evaluating what value a function approaches as the input nears a particular point. In this exercise, the goal is to determine the infinite limit as \( x \to 0 \) for the function \( f(x) = \ln(x^2) - x^{-2} \).There are several key steps in limit analysis:
  • Separate Analysis: Break down the function into its components; here it's \( \ln(x^2) \) and \( -x^{-2} \).
  • Behavior Prediction: Predict how each component behaves individually as \( x \to 0 \).
  • Combine Results: Evaluate the combination of these predictions to determine the overall behavior of the function.
By following these steps, as \( x \to 0 \), we identified that both \( 2\ln|x| \) and \( -\frac{1}{x^2} \) spiral down to \(-\infty\), culminating in the limit of \( -\infty \). This thorough analysis simplifies understanding and verification of such calculus problems.

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