Answer
$1.82,4.46$
Work Step by Step
Use a calculator, $sec\theta=-4 \Longrightarrow cos\theta=-\frac{1}{4} \Longrightarrow \theta=cos^{-1}(-\frac{1}{4})\approx1.82$ and $2\pi-1.82\approx4.46$ in $[0,2\pi)$.
Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)
by Sullivan III, Michael
Published by
Pearson
ISBN 10:
0-32193-104-1
ISBN 13:
978-0-32193-104-7
Chapter 6 - Analytic Trigonometry - Section 6.3 Trigonometric Equations - 6.3 Assess Your Understanding - Page 488: 51
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