Sum-to-Product Formulas:These formulas express a sum or difference of two trigonometric functions as a product of two other trigonometric functions, which is the inverse of product-to-sum formulas.
Trigonometric Identities:Trigonometric identities are equations that are true for all values of the variables, and they can be used to simplify and manipulate trigonometric expressions.
Trigonometric Equations: Trigonometric equations are equations that involve trigonometric functions, and they can be solved using various techniques, including the use of product-to-sum formulas.