Definition of The Derivative Function The function f defined by the formula f(x)=lim I(x+h)-f(x) h-→0 h which is called the derivative of fwith respect to x. The domain of f consists of all x in the domain of ffor which the limit exists. Definition of The Derivative Function ⚫ The function f’ defined by the formula which is called the derivative of f with respect to x. The domain of f’ consists of all x in the domain of f for which the limit exists. 0 ( ) ( ) '( ) limh f x h f x f x → h + − =