Math Forum: Ask Dr. Math FAQ: Trigonometry Formulas
[Back to Contents] Identities sec(x) = 1/cos(x), csc(x) = 1/sin(x), cot(x) = 1/tan(x), tan(x) = sin(x)/cos(x), cot(x) = cos(x)/sin(x). sin(-x) = -sin(x), cos(-x) = cos(x), tan(-x) = -tan(x), cot(-x) = -cot(x), sec(-x) = sec(x), csc(-x) = -csc(x)....