Law o cosines

Figur 1 – A triangle. The angles Template:Math (or Template:Math), Template:Math (or Template:Math), an Template:Math (or Template:Math) are respectively opposite the sides Template:Math, Template:Math, an Template:Math.

In trigonometry, the law o cosines (an aa kent as the cosine formula or cosine rule) relates the lenths o the sides o a triangle tae the cosine o ane o its angles. Uisin notation as in Fig. 1, the law o cosines states

$c^{2}=a^{2}+b^{2}-2ab\cos \gamma \,$

whaur Template:Math denotes the angle conteened atween sides o lenths Template:Math an Template:Math an opposite the side o lenth Template:Math.