Precalculus (6th Edition) Blitzer

Published by Pearson
ISBN 10: 0-13446-914-3
ISBN 13: 978-0-13446-914-0

Chapter 2 - Section 2.5 - Zeros of Polynomial Functions - Exercise Set - Page 377: 37

Answer

2 or 0 positive real zeros. 2 or 0 negative real zeros.

Work Step by Step

Step 1. Given the function $f(x)=2x^4-5x^3-x^2-6x+4$, we can see that $f(x)$ has 2 sign changes. Thus, based on Descartes’s Rule of Signs, the function may have 2 or 0 positive real zeros. Step 2. Testing the function $f(-x)=2x^4+5x^3-x^2+6x+4$, we can see that $f(-x)$ has 2 sign changes. Thus, based on Descartes’s Rule of Signs, the function may have 2 or 0 negative real zeros.
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.