Simplify expressions using fundamental identities

The video tutorial explains how to simplify a trigonometric expression involving tangent squared of Theta by using Pythagorean identities. The instructor identifies the relevant identity, 1 plus tangent squared of Theta equals secant squared of Theta, and demonstrates how to rewrite the expression using this identity. The expression is further simplified by reciprocating secant squared to cosine squared, providing a clear method for simplifying similar trigonometric expressions.

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