Precalculus (6th Edition) Blitzer

Published by Pearson
ISBN 10: 0-13446-914-3
ISBN 13: 978-0-13446-914-0

Chapter 5 - Section 5.2 - Sum and Difference Formulas - Concept and Vocabulary Check - Page 668: 1


Identity for $\cos \left( x+y \right)$ is expressed as $\cos x\cos y-\sin x\sin y$.

Work Step by Step

From the sum formula of cosines, the cosine of the sum of two angles, say A and B, is expressed as, $\cos \left( A+B \right)=\cos A\cos B-\sin A\sin B$ Thus, for angles x and y, $\cos \left( x+y \right)=\cos x\cos y-\sin x\sin y$
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.