Trigonometric Addition Formulas

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Theorem

Sine of Sum

$\map \sin {a + b} = \sin a \cos b + \cos a \sin b$


Cosine of Sum

$\map \cos {a + b} = \cos a \cos b - \sin a \sin b$


Tangent of Sum

$\map \tan {a + b} = \dfrac {\tan a + \tan b} {1 - \tan a \tan b}$


Also defined as

Some sources include the Trigonometric Subtraction Formulas in with the Trigonometric Addition Formulas.

Other sources lump the Trigonometric Addition Formulas and Trigonometric Subtraction Formulas together and call them all Compound Angle Formulas.


Also known as

The Trigonometric Addition Formulas are also known as the Trigonometric Addition Formulae.

They are also known as:

Some sources use the term Trigonometric Addition Formulas as a synonym for Compound Angle Formulas.


Also see


Sources