Trigonometric Addition Formulas
The trigonometric addition formulas are a set of formulas that express trigonometric functions of sums of angles in terms of the trigonometric functions of the original angles.
Trigonometric addition formulas is a high school-level concept that would be first encountered in a trigonometry course. It is listed in the California State Standards for Trigonometry.
Examples
Double-Angle Formulas: | The double-angle formulas are a set of formulas that express trigonometric functions of twice an angle in terms of the trigonometric functions of the original angle. |
Half-Angle Formulas: | A set of formulas that express trigonometric functions of half an angle in terms of the trigonometric functions of the original angle. |
Prerequisites
Cosine: | The cosine is the ratio of the length of an angle's adjacent side to the length of the hypotenuse in a right triangle. |
Sine: | The sine is the ratio of the length of a given angle's opposite side to the length of the hypotenuse in a right triangle. |
Tangent: | (1) In trigonometry, the tangent of an angle is the ratio of the length of a given angle's opposite side to the length of the angle's adjacent side in a right triangle. (2) In geometry, two figures are said to be tangent to one another if they "just touch". |