Answer
True
Work Step by Step
$\cos (30^{\circ}+20^{\circ}) = \cos 30^{\circ}\cos20^{\circ} - \sin 30^{\circ}\sin20^{\circ}$
$\cos 50^{\circ} = 0.8137976813 - 0.1710100717$
$0.6427876097= 0.6427876097$
Trigonometry (10th Edition)
by Lial, Margaret L.; Hornsby, John; Schneider, David I.; Daniels, Callie
Published by
Pearson
ISBN 10:
0321671775
ISBN 13:
978-0-32167-177-6
Chapter 2 - Acute Angles and Right Triangles - Section 2.3 Finding Trigonometric Function Values Using a Calculator - 2.3 Exercises - Page 65: 57
Update this answer!
You can help us out by revising, improving and updating this answer.
Update this answerAfter 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.
