This trigonometry laws and identities help sheet contains the law of cosines, law of sines, and law of
tangents. It also contains the following identities: tangent identities, reciprocal identities,
Pythagorean identities, periodic identities, even/odd identities, double angle identities, half angle
identities, product to sum identities, sum to product identities, sum/difference identities, and
cofunction identities.