### Home > A2C > Chapter 8 > Lesson 8.1.6 > Problem8-91

8-91.

Calculate the value of each expression below. Each measure is given in radians.

1. $\operatorname{sin}\left(4\right)$

$−0.76$
1. $\operatorname { sin } ( \frac { 4 \pi } { 3 } )$
$\text{Since }\frac{4\pi}{3} \text{ is related to the }30^{\circ}-60^{\circ}-90^{\circ}\text{ angles, this one}$
$\text{has an exact answer. Locate it on the unit circle.}$
$\text{Notice that it will be a reflection (twice) of sin} \left(\frac{\pi}{3}\right).$