Skip to main content
Ch. 2 - Limits and Continuity
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 2, Problema 2.2.80a

Theory and Examples


a. If limx→0 f(x) / x² = 1, find limx→0 f(x).

Guida verificata passo dopo passo
1
First, understand the given limit: \( \lim_{x \to 0} \frac{f(x)}{x^2} = 1 \). This means that as \( x \) approaches 0, the function \( \frac{f(x)}{x^2} \) approaches 1.
To find \( \lim_{x \to 0} f(x) \), consider the behavior of \( f(x) \) as \( x \) approaches 0. Since \( \frac{f(x)}{x^2} \to 1 \), it implies that \( f(x) \) behaves like \( x^2 \) near 0.
Multiply both sides of the equation \( \frac{f(x)}{x^2} = 1 \) by \( x^2 \) to isolate \( f(x) \): \( f(x) = x^2 \cdot 1 = x^2 \).
Now, substitute \( f(x) = x^2 \) into the limit expression: \( \lim_{x \to 0} f(x) = \lim_{x \to 0} x^2 \).
Evaluate the limit \( \lim_{x \to 0} x^2 \). As \( x \to 0 \), \( x^2 \to 0 \). Therefore, \( \lim_{x \to 0} f(x) = 0 \).

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
2m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Limits

A limit is a fundamental concept in calculus that describes the behavior of a function as its input approaches a certain value. In this case, we are interested in the limit of f(x) as x approaches 0. Understanding limits is crucial for analyzing the continuity and behavior of functions at specific points.
Video consigliato:
05:50
One-Sided Limits

L'Hôpital's Rule

L'Hôpital's Rule is a method used to evaluate limits of indeterminate forms, such as 0/0 or ∞/∞. It states that if the limit of f(x)/g(x) results in an indeterminate form, the limit can be found by taking the derivative of the numerator and the derivative of the denominator. This rule can simplify the process of finding limits in complex scenarios.
Video consigliato:
5:50
Power Rules

Continuous Functions

A function is continuous at a point if the limit of the function as it approaches that point equals the function's value at that point. In this problem, if we find that limx→0 f(x) exists and equals a specific value, it indicates that f(x) is continuous at x = 0, which is essential for understanding the behavior of the function around that point.
Video consigliato:
05:34
Intro to Continuity