Trigonometry (11th Edition) Clone

Published by Pearson
ISBN 10: 978-0-13-421743-7
ISBN 13: 978-0-13421-743-7

Chapter 2 - Acute Angles and Right Triangles - Section 2.2 Trigonometric Functions of Non-Acute Angles - 2.2 Exercises - Page 62: 17


$\cos$ 30$^{\circ}$ = $\frac{-\sqrt3}{2}$ $\sec$ 30$^{\circ}$ = -$\frac{2\sqrt3}{3}$

Work Step by Step

We use the reference angle to determine the trigonometric functions. $\theta$$^{1}$ = 210$^{\circ}$ - 180$^{\circ}$ $\theta$$^{1}$ = 30$^{\circ}$ $\cos$ 30$^{\circ}$ = $\frac{-\sqrt3}{2}$ $\sec$ 30$^{\circ}$ = $\frac{2}{-\sqrt3}$ = -$\frac{2\sqrt3}{3}$
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