When a variable changes from one numerical value to another, we refer to the difference of the values as the increment of the variable; for example, if x changes from x1 to x2, then the increment equals x2 − x1. The increment is represented by the symbol Δ x, read “delta x ”; thus Δ x = x2 − x1.
Learn derivatives and differentiation of algebraic functions. Increment method, differentiation rules, and examples included.