# Differential and its relation with derivative

*Differential of a function. Geometrical meaning of a differential.*

** Differential of a function ** is a product of a derivative

*f*’(

*x*

_{0}) and an

increment of argument :

*df*=

*f*’(

x

x

_{0}) ·

*.*

Geometrical meaning of a differential is clear from Fig.2 : here *df* = CD