Thetas

Thetas is the plural form of theta, a symbol with wide usage in science and mathematics. Theta is the ninth letter of the Greek alphabet and is written as Θ in uppercase and θ in lowercase. In many contexts, thetas denote angles, parameters, and variables.

In mathematics, theta commonly represents an angle in geometry and trigonometry. It is used in polar coordinates (r, θ) and in spherical coordinates (where θ often serves as the polar angle and φ as the azimuthal angle). It also appears as a general input variable in formulas, with values typically given in radians.

In computer science, Big Theta notation is used to describe a tight asymptotic bound. If a function f(n) = Θ(g(n)), then f grows at the same rate as g up to constant factors. This provides a precise description of growth, in contrast to Big-O or Big-Omega bounds which give upper or lower limits only.

In statistics and probability, theta is frequently used to denote a parameter of a distribution or a model, such as a vector θ = (θ1, θ2, …). In Bayesian and likelihood-based methods, θ represents the parameters to be estimated or inferred from data.

In physics and related fields, theta commonly denotes a polar angle in spherical-coordinate systems or other angular measures. The term also appears in various special functions, such as the theta function in complex analysis and number theory, which is named after the same Greek letter.

Overall, thetas appear across disciplines as a versatile symbol for angles, parameters, and variables.