Algebra and Trigonometry 10th Edition

Published by Cengage Learning
ISBN 10: 9781337271172
ISBN 13: 978-1-33727-117-2

Chapter 7 - 7.2 - Verifying Trigonometric Identities - 7.2 Exercises - Page 521: 67


$-1\leq sin~θ\leq1$ $0\leq\sqrt {1-cos^2θ}\leq1$ Example: $θ=225°$: $sin~225°=-\frac{\sqrt 2}{2}\ne\sqrt {1-cos^2225°}=\sqrt {1-(\frac{\sqrt 2}{2})^2}=\frac{\sqrt 2}{2}$

Work Step by Step

$sin^2θ+cos^2θ=1$ $sin^2θ=1-cos^2θ$ $sin~θ=±\sqrt {1-cos^2θ}$
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