2cos2

2cos2 is the real number obtained by multiplying 2 by the cosine of the angle 2. In standard mathematical practice, the angle 2 is interpreted in radians unless a different unit is specified. As a constant, it does not vary with a variable.

Numerically, cos(2 radians) is approximately -0.4161468365, so 2 cos(2) ≈ -0.8322936731. The value depends on the unit of the angle: if the angle were in degrees, 2 cos(2°) ≈ 1.998781654, which shows how changing the angle unit changes the result.

In trigonometric terms, 2 cos θ can be related to complex exponentials via 2 cos θ = e^{iθ} + e^{-iθ}. The expression 2 cos 2 thus equals e^{i2} + e^{-i2} when θ = 2, illustrating its connection to harmonic analysis and Fourier-style representations. The absolute bound |2 cos θ| ≤ 2 holds for all real θ, since |cos θ| ≤ 1.

Because it is a constant rather than a function of a variable, 2cos2 often appears as a numeric factor in equations or as a fixed coefficient in identities and computations. Its interpretation hinges on the angle unit and the context in which it appears.