Precalc Double Angle + Sum and Difference Formulas

Trig identities to memorize.

sin2x

2sinxcosx

cos2x

cos^2x-sin^2x

cos2x

1-2sin^2x

cos2x

2cos^2x-1

tan2x

2tanx/1-tan^2x

sin(u+-v)

sin(u)cos(v)+-cos(u)sin(v)

cos(u+-v)

cos(u)cos((v)-+sin(u)sin(v)

tan(u+-v)

tan(u)+-tan(v) / (1-+tan(u)tan(v))