Evaluate for theta between 0 and 2pi

The video tutorial explains how to evaluate the angle Theta when given a coordinate point, specifically focusing on the cosine value of -√2/2. The instructor emphasizes the importance of understanding the unit circle, particularly the first quadrant, to solve such problems. The tutorial details how cosine represents the X value and identifies angles where the cosine is negative, specifically at 3π/4 and 5π/4.

How do you determine the reflection points on the unit circle for a given cosine value?

What are the two angles where cosine equals -sqrt(2)/2?