### Home > PC > Chapter 4 > Lesson 4.3.2 > Problem4-137

4-137.

Find the exact value of each of the following without using a calculator or your unit circle.

1. $\text{cos }( \frac { - 5 \pi } { 6 } )$

$-\frac{\sqrt3}{2}$

1. $\text{tan }( \frac { 31 \pi } { 4 } )$

$−1$