Question

4. Evaluate the following Trigonometric Functions giving exact values and explain how you found your answer.A. cos (- 120°)B. Tan 5pi/6

Answer 1

PART A:

Determine the value of trigonometric expression.

$\begin{gathered} \cos (-120)=\cos (120) \\ =\cos (90+30) \\ =-\sin 30 \\ =-\frac{1}{2} \end{gathered}$

PART B:

Determine the value of trigonometric expression.

$\begin{gathered} \tan (\frac{5\pi}{6})=\tan (\pi-\frac{\pi}{6}) \\ =-\tan \frac{\pi}{6} \\ =-\frac{1}{\sqrt[]{3}} \end{gathered}$