### Home > INT3 > Chapter 10 > Lesson 10.2.1 > Problem10-107

10-107.

Use reference angles, the unit circle, and the fact that cos = to write three other true statements using cosine and angles that are multiples of . Homework Help ✎

Draw a unit circle diagram for the given angle.

Reflect the triangle in each of the 4 quadrants. Quadrant 2 is shown for you.

$\text{cos}\left( \frac{2\pi}{3} \right)=-\frac{1}{2}$