Trigonometry 7th Edition

Published by Cengage Learning
ISBN 10: 1111826854
ISBN 13: 978-1-11182-685-7

Chapter 1 - Section 1.3 - Definition I: Trigonometric Functions - 1.3 Problem Set - Page 32: 52


Quadrant II

Work Step by Step

By Definition I- $\sin\theta$ =$ \frac{y}{r}$ Given $\sin\theta$ is positive, hence y is positive as r being distance can not be negative. 'y' is positive in Quadrant I and II. $\cos\theta$ =$ \frac{x}{r}$ If $\cos\theta$ is negative, then x is negative as r being distance can not be negative. x is negative in Quadrant II and III only. Concluding from both of the above statements, both can be true only when terminal side lies in Quadrant II
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