Trigonometry (10th Edition)

Published by Pearson
ISBN 10: 0321671775
ISBN 13: 978-0-32167-177-6

Chapter 6 - Test - Page 287: 14

Answer

$\left\{0.3649\text{ radians}, 3.5065\text{ radians}, 1.2059\text{ radians}, 4.3475\text{ radians}\right\}$

Work Step by Step

Multiply $2$ t both sides of the equation: $2\sin{x}\cos{x} = \frac{2}{3}$ RECALL: $\sin{(2x)} = 2\sin{x}\cos{x}$ Use the identity above to obtain: $2\sin{x}\cos{x}=\frac{2}{3} \\\sin{(2x)} = \frac{2}{3} \\2x=\sin^{-1}{(\frac{2}{3})}$ Use a scientific calculator's inverse sine function to obtain: $2x=0.7297276562$ radians or $2x=2.411864997$ \radians Since the period of $sin{x}$ is $2\pi$, add $2\pi$ to each solution above to obtain two more solutions: $2x= 7.012912963$ radians or $2x=8.695050305$ radians Divide both sides of each equation by $2$, then round off the answer to four decimal places to obtain: $x\approx 0.3649, 3.5065, 1.2059, 4.3475$ radians
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