Trigonometry (10th Edition)

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: 33

Answer

Quadrant I

Work Step by Step

1.$\cos\theta=\frac{x}{r}$ If cosine is positive, that means x must be positive (since r is always positive) That can be only I and IV quadrants 2.$\sin\theta=\frac{y}{r}$ If sine is positive, that means y must be positive (since r is always positive) That can be only I and II quadrants 3. For both sine and cosine to be positive, we must be in Quadrant I
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