Precalculus: Mathematics for Calculus, 7th Edition

Published by Brooks Cole
ISBN 10: 1305071751
ISBN 13: 978-1-30507-175-9

Chapter 1 - Section 1.8 - Inequalities - 1.8 Exercises - Page 91: 131

Answer

a) $x^2 \leq y^2$ b) $\sqrt{xy} \leq \frac{(x+y)}{2}$

Work Step by Step

a) Re-arrange the first inequality such as $x^2 \leq xy$ ...(1) Also, $xy \leq y^2$ ....(2) Now, let us combine the both inequalities (1) and (2). Also, we have $x^2 \leq xy \leq y^2$ This gives: $x^2 \leq y^2$ b) Re-arrange the first inequality such as Also, $\sqrt{xy} \gt \frac{(x+y)}{2}$ This gives: $xy \gt \frac{x^2+2xy+y^2}{4}$ or, $x^2-2xy+y^2 \lt 0$ $(x-y)^2 \lt 0$ As the square exprssion is alwsuys being non-negative. Thus, we have $\sqrt{xy} \leq \frac{(x+y)}{2}$
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.