Trigonometric Functions:The fundamental trigonometric functions are sine, cosine, tangent, and their reciprocals, which describe the relationship between the sides and angles of a right triangle.
Product-to-Sum Formulas:The product-to-sum formulas are the inverse of the sum-to-product formulas, allowing for the conversion of products of trigonometric functions into sums of trigonometric functions.
Trigonometric Identities:Trigonometric identities are mathematical statements that hold true for all values of the variables involved, and they are used to simplify and manipulate trigonometric expressions.