How to simplify a rational trigonometric expression

The video tutorial demonstrates how to simplify a trigonometric expression using Pythagorean identities. The instructor explains the process of substituting sine squared with cosine squared and emphasizes the importance of using the correct variable. The tutorial concludes with the final simplification of the expression, highlighting the use of the distributive property and rewriting secant in terms of cosine.

What is the significance of transferring variables when simplifying trigonometric identities?

Explain how secant can be rewritten in terms of cosine in the final steps of simplification.