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Trigonometry Formulas

Double Angle Formulars
double angle formulas
Power Reducing Formulars
power reducing formulas
Cofunction Identities
cofunction identities
Negative Angle Identities
sin (-x) = - sin x
cos (-x) = cos x
csc (-x) = -csc x
tan (-x) = -tan x
sec (-x) = sec x
cot (-x) = -cot x
Sum and Difference Formulas
sin (u + v) = sin u cos v + cos u sin v
sin (u - v) = sin u cos v - cos u sin v
cos (u + v) = cos u cos v - sin 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)
tan (u - v) = (tan u - tan v) / (1 + tan u tan v)
Sum to product Fomulas
sin u + sin v = 2 sin [(u + v) / 2] cos [(u - v) / 2]
sin u - sin v = 2 cos [(u + v) / 2] sin [(u - v) / 2]
cos u + cos v = 2 cos [(u + v) / 2] cos [(u - v) / 2]
cos u - cos v = -2 sin [(u + v) /2] sin [(u - v) / 2]
Product to Sum Formulas
sin u sin v = [cos (u - v) - cos (u + v)] / 2
cos u cos v = [cos (u - v) + cos (u + v)] / 2
sin u cos v = [sin (u + v) + sin (u - v)] / 2
cos u sin v = [sin (u + v) - sin (u - v)] / 2