Trigonometry 7th Edition

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: 31

Answer

See the steps.

Work Step by Step

$LHS = \cos{120} = -\dfrac{1}{2}$ $RHS = \cos^2 {60} - \sin^2 {60} = \left(\dfrac{1}{2}\right)^2 - \left(\dfrac{\sqrt{3}}{2}\right)^2$ $RHS = -\dfrac{1}{2}$ $LHS = RHS$
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.