backward difference
Mathematics
noun
Each of a set of finite differences calculated by subtracting a previous value of a function f(x) from the present value when the argument x is varied by a small negative amount; frequently attributive.
- In symbolic terms, a backward difference ∇h = f(x) − f(x − h), in contrast to a forward difference, where ∆h = f(x + h) − f(x)..
Origin
Early 20th century; earliest use found in Annals of Mathematics.