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: 32

Answer

$\frac{2}{5}$

Work Step by Step

$sin^{2}t$ + $cos^{2}t$ = 1 sin t = $\frac{\sqrt {21}}{5}$ $(\frac{\sqrt {21}}{5})^{2}$ + $cos^{2}t$ = 1 $\frac{21}{25}$ + $cos^{2}t$ = 1 $cos^{2}t$ = 1 -$\frac{21}{25}$ $cos^{2}t$ = $\frac{4}{25}$ cos t = $\sqrt \frac{4}{25}$ = $\frac{2}{5}$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.