Precalculus (6th Edition)

Published by Pearson
ISBN 10: 013421742X
ISBN 13: 978-0-13421-742-0

Chapter 6 - The Circular Functions and Their Graphs - 6.2 The Unit Circle and Circular Functions - 6.2 Exercises - Page 588: 14


(a) $\sin{\frac{\pi}{2}}=0$ (b) $\cos{\frac{\pi}{2}}=-1$ (c) $\tan{\frac{\pi}{2}}=0$

Work Step by Step

Using Figure 13 on page 579 of this book, the angle $\pi$ intersects the unit circle at the point $(-1, 0)$. RECALL: In a unit circle, (1) $\cos{s} = x$ (2) $\sin{s} = y$ (3) $\tan{s} = \dfrac{y}{x}$ Thus, using the definitions above to obtain: (a) $\sin{\frac{\pi}{2}}=0$ (b) $\cos{\frac{\pi}{2}}=-1$ (c) $\tan{\frac{\pi}{2}}=\dfrac{0}{-1}=0$
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