Precalculus (6th Edition) Blitzer

Published by Pearson
ISBN 10: 0-13446-914-3
ISBN 13: 978-0-13446-914-0

Chapter 4 - Section 4.2 - Trigonometric Functions: The Unit Circle - Exercise Set: 31

Answer

$\frac{5}{8}$

Work Step by Step

$sin^{2}t$ + $cos^{2}t$ = 1 sin t = $\frac{\sqrt {39}}{8}$ $(\frac{\sqrt {39}}{8})^{2}$ + $cos^{2}t$ = 1 $\frac{39}{64}$ + $cos^{2}t$ = 1 $cos^{2}t$ = 1 -$\frac{39}{64}$ $cos^{2}t$ = $\frac{25}{64}$ cos t = $\sqrt \frac{25}{64}$ = $\frac{5}{8}$
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