Evaluating the difference of two angles for the cosine function

The video tutorial covers the evaluation of the cosine of the difference of two angles, focusing on creating triangles in the second quadrant and applying the Pythagorean theorem. The instructor explains the importance of using the correct signs for triangle sides based on their quadrant and demonstrates the application of the cosine difference formula. The session concludes with a Q&A segment addressing common student mistakes.

Describe the difference formula for cosine of two angles as mentioned in the video.

How do the values of sine and cosine change based on the quadrant of the triangle?