See also: #Product-to-sum and sum-to-product identitiesThese are also known as the addition and subtraction theorems or formulae. They were originally established by the 10th century Persian mathemati ...
AnglesThis article uses Greek letters such as alpha (α), beta (β), gamma (γ), and theta (θ) to represent angles. Several different units of angle measure are widely used, including degrees, radian ...
In mathematics, trigonometric identities are equalities that involve trigonometric functions and are true for every single value of the occurring variables. Geometrically, these are identities involvi ...
