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 89: 73

Answer

$(-\infty, -1) ∪ (0, \infty)$
1554953102

Work Step by Step

$$x^4>x^2$$ Subtract $x^2$ $$x^4-x^2>0$$ Factor out $$x^2(x^2-1)>0$$ $$x^2(x-1)(x+1)>0$$ So, we have key points: $x+1=0$ ; $x=-1$ $x=0$ $x-1=0$ ; $x=1$ Which gives us following intervals: $(-\infty, -1)$ - Positive $(-1, 0)$ - Negative $(0, 1)$ - Negative $(1, \infty)$ - Positive We need open interval of all positive set of values, so the answer is: $(-\infty, -1) ∪ (0, \infty)$
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.