deltax

Delta x, written as Δx, denotes a finite change or increment in the variable x. It contrasts with dx, which represents an infinitesimal or differential change in x. The symbol Δx is used across mathematics, physics, engineering, and numerical analysis to emphasize a finite difference between two states.

In calculus, Δx is the input increment used in finite difference quotients. The average rate of change over an interval is Δf/Δx. The derivative f'(x) is the limit of Δf/Δx as Δx approaches zero.

In physics and kinematics, Δx represents displacement along the x-axis, equal to x2 − x1, often with Δt for the time interval. If velocity is constant, Δx = v Δt; for nonuniform motion, Δx = ∫ v dt over the interval.

In numerical methods, Δx is the grid spacing or step size. Smaller Δx improves accuracy for finite difference schemes but increases computation.

In measurement, Δx may denote the uncertainty or resolution of the x-coordinate in an experiment; it quantifies possible error in the position measurement.

Other uses: in data analysis and algorithms, Δx may define step sizes in loops or updates, and in some fields Δx is used interchangeably with dx in informal contexts.