Trigonometry (11th Edition) Clone

Published by Pearson
ISBN 10: 978-0-13-421743-7
ISBN 13: 978-0-13421-743-7

Chapter 6 - Inverse Circular Functions and Trigonometric Equations - Section 6.1 Inverse Circular Functions - 6.1 Exercises - Page 264: 15



Work Step by Step

$$y=\cos^{-1}(-1)$$ First, we see that the domain of inverse cosine function is $[-1,1]$. $-1$ lies in this range, so $\cos^{-1}(-1)$ does exist. Also, it should be noted that the range of inverse cosine function is $[0,\pi]$. In other words, $y\in[0,\pi]$. We can rewrite $y=\cos^{-1}(-1)$ into $\cos y=-1$ In the range $[0,\pi]$, we find that only $\cos\pi=-1$ That means, the exact value of $y$ here is $$y=\pi$$
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.