Answer
$\cos{(60)}=\dfrac{1}{2} $
Work Step by Step
$\cos{(A-B)} = \cos{A} \cos{B} + \sin{A} \sin{B}$
$\cos{(15)} \cos{(75)} + \sin{(15)} \sin{(75)} \\= \cos{(15-75)} = \cos{(-60)} = \cos{(60)}=\dfrac{1}{2}$
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 5.2 - Sum and Difference Formulas - 5.2 Problem Set - Page 289: 34
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.
