How to factor a trigonometric expression

The video tutorial introduces trinomials and discusses their characteristics. It emphasizes the importance of understanding trigonometric functions and suggests simplifying problems by using variables X and Y. The tutorial explains factoring techniques and demonstrates how to apply these concepts to solve equations, highlighting the representation of X as the sine of X.

What is the most difficult aspect of the topic discussed according to the teacher?

Why does the teacher suggest forgetting about trigonometric functions when writing the expression?