4sin'x – 1 1. 2sinx + 1 = 2sinx – 1 sin'x – 2sinx + 1 2. = sinx – 1 sinx – 1 3. ( sinx - cos x)(sinx + cos x) = 1 - 2 cos?x 4. (tanx)(1 - cot x) = tan x - 1 1 1 5. sin x cosx – sinx CosY sin xcosx

Equations that give the relation between different trigonometric functions and are true for any value of the variable for the domain. There are six trigonometric functions: sine, cosine, tangent, cotangent, secant, and cosecant.