Infinitesimal
Infinitesimal
In a phraseology which is logically inexact but nevertheless common, an infinitesimal is a quantity, or a variable, whose limit is 0. Thus in considering the limit of f(x) as x approaches c, if this limit is 0 the “quantity” f(x) may be said to be an infinitesimal; or in considering the limit of f(x) as x approaches 0, the “quantity” x may be said to be an infinitesimal. (See the article limit.) — A.C.