### Home > PC > Chapter 4 > Lesson 4.2.3 > Problem4-104

4-104.

Find the exact value of each of the following trig expressions without using a calculator.

1. $\text{cos }( \frac { 7 \pi } { 6 } )$

Draw a unit circle with reference angle.

1. $\text{sin }( \frac { 3 \pi } { 2 } )$

Follow the hint in part (a).

1. $\text{sec }( \frac { 4 \pi } { 3 } )$

$\sec(\theta)=\frac{1}{\cos(\theta)}$

1. $\text{tan }( \frac { 2 \pi } { 3 } )$

Follow the hint in part (a).