cot2

Cot2 is commonly used to denote the value of the cotangent function at the argument 2, i.e., cot(2). In trigonometry, cot x is defined as cos x divided by sin x. Evaluating at x = 2 (radians) yields sin 2 ≈ 0.9092974268 and cos 2 ≈ −0.4161468365, so cot 2 = cos 2 / sin 2 ≈ −0.4576575675. Because 2 radians lies in the second quadrant, cot 2 is negative.

Properties of cotangent include that cot x has period π, and cot 2 is a real number since sin 2 ≠ 0 (sin x = 0 at x = kπ). The cotangent function relates to tangent via cot x = 1 / tan x, and also cot x = cos x / sin x.

Ambiguity may arise in notation. Some contexts use cot2 to mean (cot x)^2 or other shorthand; however, the standard square is written cot^2 x. If the intent is cot(2) with degrees or to denote a squared value, the interpretation changes. The default assumption in mathematical texts is radians unless specified.

See also: cotangent, trigonometric identities, cotangent squared.