Calculus: Early Transcendentals 8th Edition

Published by Cengage Learning
ISBN 10: 1285741552
ISBN 13: 978-1-28574-155-0

Chapter 2 - Section 2.4 - The Precise Definition of a Limit - 2.4 Exercises - Page 114: 31

Answer

$\lim\limits_{x \to -2} (x^2-1) = 3$

Work Step by Step

Let $\epsilon \gt 0$ be given. Let $\delta = min\{1, \frac{\epsilon}{5}\}$ Suppose that $\vert x-(-2) \vert \lt \delta$ Then: $\vert (x^2-1) - 3\vert = \vert x^2-4\vert = \vert (x-2)(x+2)\vert = \vert (x-2)\vert \cdot \vert(x+2)\vert \lt (5)(\delta) \leq (5)(\frac{\epsilon}{5}) = \epsilon$ Therefore, $\lim\limits_{x \to -2} (x^2-1) = 3$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.