### Home > PC3 > Chapter 2 > Lesson 2.2.2 > Problem2-64

2-64.

Evaluate each of the following expressions by using special right triangles and the unit circle (give exact values).

1. $\sin\left(\frac{4\pi}{3}\right)$

1. Draw a unit circle and locate the angle.

2. Draw a right triangle with the base is the x-axis.

3. Label the side lengths.

4. Choose the y-value for the sine!

2. $\cos\left(\frac{11\pi}{3}\right)$

3. $\sin\left(-\frac{5\pi}{6}\right)$

4. $\cos\left(-\frac{2\pi}{3}\right)$