How to evaluate for cos without using a calculator or the unit circle

The video tutorial explains how to evaluate trigonometric functions using reference angles. It covers the concept of coterminal angles, how to determine the quadrant of an angle, and the significance of reference angles in trigonometry. The tutorial emphasizes the importance of understanding the quadrant to determine the sign of trigonometric values and provides a practical example using the cosine function.

What is the significance of reference angles in evaluating trigonometric functions?

How do you find a coterminal angle for 23π / 6?

Explain how to determine the quadrant in which an angle lies.

What is the reference angle for 11π / 6, and how is it calculated?

Discuss the relationship between the cosine of an angle and its reference angle.

In which quadrant is the angle 11π / 6 located, and what does that imply about the sign of cosine?

What is the cosine value of π / 6, and how can it be derived without a calculator?