Trigonometry (10th Edition)

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

Chapter 3 - Radian Measure and the Unit Circle - Section 3.3 The Unit Circle and Circular Functions - 3.3 Exercises - Page 118: 76

Answer

$(x,y) = (-0.73, -0.69)$

Work Step by Step

The radius of the circle is 1. We can find the angle $\theta$: $\theta = s~r$ $\theta = (-3.9)(1)$ $\theta = -3.9~radians$ We can find $x$: $\frac{x}{r} = cos~\theta$ $\frac{x}{1} = cos~\theta$ $x = cos~(-3.9~rad)$ $x = -0.73$ We can find $y$: $\frac{y}{r} = sin~\theta$ $\frac{y}{1} = sin~\theta$ $y = sin~(-3.9~rad)$ $y = -0.69$ $(x,y) = (-0.73, -0.69)$
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