Calculus (3rd Edition)

Published by W. H. Freeman
ISBN 10: 1464125260
ISBN 13: 978-1-46412-526-3

Chapter 7 - Exponential Functions - 7.8 Inverse Trigonometric Functions - Exercises - Page 374: 9



Work Step by Step

Since $\cos\frac{3\pi}{2}=0$, we have $$\cos^{-1}\left(\cos\frac{4\pi}{3}\right)=\cos^{-1}\left(0\right)=\frac{\pi}{2}.$$
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.