Trigonometry (10th Edition)

Published by Pearson
ISBN 10: 0321671775
ISBN 13: 978-0-32167-177-6

Chapter 2 - Acute Angles and Right Triangles - Section 2.2 Trigonometric Functions of Non-Acute Angles - 2.2 Exercises: 74



Work Step by Step

As we have seen examples of, we know that $\cos$ 120$^{\circ}$ = -$\frac{1}{2}$ Therefore: $cos$ 120$^{\circ}$ = -0.5 So, as the angle of $\cos$ gets larger, the result gets smaller. Therefore, $\cos$ 115$^{\circ}$ would be slightly more than $\cos$ 120$^{\circ}$. -0.4 is the option closest to -0.5
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