Learn how to evaluate using the half angle formula of sine

The video tutorial explains the half angle formula for sine and demonstrates how to find the sine of 3π/8 using this formula. It covers solving for U, finding the cosine of 3π/4 using the unit circle, and simplifying the resulting expression. The tutorial emphasizes understanding each step and the importance of the unit circle in trigonometry.

How do you determine the cosine of three π / 4 using the unit circle?

Why is the sine of the angle in the second quadrant considered positive?

What steps are involved in simplifying the expression involving sine and cosine?