Trigonometry (10th Edition)

by Lial, Margaret L.; Hornsby, John; Schneider, David I.; Daniels, Callie

Published by Pearson

ISBN 10: 0321671775

ISBN 13: 978-0-32167-177-6

Chapter 1 - Trigonometric Functions - Section 1.4 Using the Definitions of the Trigonometric Functions - 1.4 Exercises - Page 36: 32

Answer

Quadrant I and IV

Work Step by Step

$\cos\theta=\frac{x}{r}$ If cosine is positive, that means x must be positive (since r is always positive) That can be only I and IV quadrants

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