Notes
cosine rule

Cosine Rule

The cosine rule extends Pythagoras' Theorem to all triangles.

CosineRule.png?

With side lengths and angles as in the above diagram then:

c 2=a 2+b 2−2abcos(C) c^2 = a^2 + b^2 - 2 a b \cos(C)

(and the same with other permutations of the letters)

Created on June 24, 2021 10:38:22 by Andrew Stacey?