Precalculus (6th Edition) Blitzer

Published by Pearson
ISBN 10: 0-13446-914-3
ISBN 13: 978-0-13446-914-0

Chapter 4 - Review Exercises - Page 644: 31

Answer

The values of the six trigonometric functions of $\theta $ are $\sin \theta =\frac{5\sqrt{89}}{89},\cos \theta =\frac{8\sqrt{89}}{89},\tan \theta =\frac{5}{8},\csc \theta =\frac{\sqrt{89}}{5},\sec \theta =\frac{\sqrt{89}}{8}\text{,}\cot \theta =\frac{8}{5}$

Work Step by Step

By using the Pythagorean Theorem, calculate the hypotenuse AB as show below: $\begin{align} & AB=\sqrt{A{{C}^{2}}+B{{C}^{2}}} \\ & =\sqrt{{{8}^{2}}+{{5}^{2}}} \\ & =\sqrt{89} \end{align}$ Now, calculate the sine function as follows: $\begin{align} & \sin \theta =\frac{BC}{AB} \\ & =\frac{5}{\sqrt{89}} \\ & =\frac{5}{\sqrt{89}}\times \frac{\sqrt{89}}{\sqrt{89}} \\ & =\frac{5\sqrt{89}}{89} \end{align}$ Then, calculate the cosine function as follows: $\begin{align} & \cos \theta =\frac{AC}{AB} \\ & =\frac{8}{\sqrt{89}} \\ & =\frac{8}{\sqrt{89}}\times \frac{\sqrt{89}}{\sqrt{89}} \\ & =\frac{8\sqrt{89}}{89} \end{align}$ Then, calculate the tangent function as follows: $\begin{align} & \tan \theta =\frac{BC}{AC} \\ & =\frac{5}{8} \end{align}$ Then, calculate the cosecant function as follows: $\begin{align} & \csc \theta =\frac{AB}{BC} \\ & =\frac{\sqrt{89}}{5} \end{align}$ Then, calculate the secant function as follows: $\begin{align} & \sec \theta =\frac{AB}{AC} \\ & =\frac{\sqrt{89}}{8} \end{align}$ And finally calculate the cotangent function as follows: $\begin{align} & \cot \theta =\frac{AC}{BC} \\ & =\frac{8}{5} \end{align}$
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.