Answer
False
Work Step by Step
We have the following identities
$\cos(x+y)=\cos x \cos y -\sin x \sin y$
so the right answer for $cos(a+b)$ must be
$\cos(a+b)=\cos a \cos b - \sin a \sin b$
Calculus with Applications (10th Edition)
by Lial, Margaret L.; Greenwell, Raymond N.; Ritchey, Nathan P.
Published by
Pearson
ISBN 10:
0321749006
ISBN 13:
978-0-32174-900-0
Chapter 13 - The Trigonometric Functions - Chapter Review - Review Exercises - Page 701: 4
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.
