Answer
$\cos{30}$
Work Step by Step
$\cos{2x} = \cos^2 {x}- \sin^2 {x}$
$\cos^2 {15} - \sin^2 {15} = \cos{30}$
Trigonometry 7th Edition
by McKeague, Charles P.; Turner, Mark D.
Published by
Cengage Learning
ISBN 10:
1111826854
ISBN 13:
978-1-11182-685-7
Chapter 5 - Section 5.3 - Double-Angle Formulas - 5.3 Problem Set - Page 297: 36
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.
