Mo logo [home] [lexicon] [problems] [tests] [courses] [auxiliaries] [notes] [staff] german flag

Mathematics-Online lexicon:

Addition Theorems for Sine and Cosine


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z overview

For the trigonometric functions $ \sin(x)$ and $ \cos(x)$ the following relations holds:

  1. $ \cos(\alpha+\beta) = \cos\alpha\cos\beta - \sin\alpha\sin\beta$
  2. $ \sin(\alpha+\beta) = \sin\alpha\cos\beta + \sin\beta\cos\alpha$

Especially:

$\displaystyle \cos (2\alpha)=\cos^2 \alpha-\sin^2 \alpha, \qquad \sin
(2\alpha)=2\sin \alpha \cos \alpha$

see also:


[Annotations] [Examples]

  automatically generated 4/ 7/2008