Evaluating for the sine of an angle using the difference formula

The video tutorial explains how to find the sine of 105 degrees using angle subtraction. It begins by rewriting 105 degrees as 135 degrees minus 30 degrees and introduces the sine subtraction formula. The instructor clarifies the formula's application, emphasizing the importance of understanding angle subtraction. The unit circle is used to evaluate the angles, and the final calculations are demonstrated, resulting in the sine of 105 degrees. The lesson concludes with factoring and simplifying the result.

How do you determine the cosine of 135 degrees?

Describe the process of factoring out common terms in the final expression.