### Home > CCA2 > Chapter 8 > Lesson 8.3.2 > Problem 8-155

8-155.

For each equation, find two solutions ** **

Recall that

so the reference angle will be . In which quadrants is cosine negative? Sketch a unit circle with right triangles with

angles at the origin in the second and third quadrants. What are the circular angles? andNow convert the angles into radians.

See part (a).

If

, .

Remember the side ratios of

right triangles.