TRIGONOMETRY IDENTITIES: Trigonometric identities are mathematical equations that are true for all values of the variables involved, where both sides of the equation are defined. They are essential tools for simplifying trigonometric expressions and solving equations. These identities are derived from the definitions of trigonometric functions and the Pythagorean theorem. MAJOR TRIGONOMETRY IDENTITIES Reciprocal Identities: These relate each trigonometric function to its reciprocal: csc θ = 1/si