Derivation is a calculation method in mathematical calculation, and its definition is the limit of the quotient between the increment of dependent variable and the increment of independent variable when the increment of independent variable tends to zero.

When a function has a derivative, it is said to be derivative or differentiable. The differentiable function must be continuous. Discontinuous functions must be non-differentiable.

The change of the first derivative If the domain of a function is all real numbers, the function is defined in the domain of real numbers. The differentiability of a function in a domain requires some conditions.

First of all, to make the function f differentiable at one point, then the function must be continuous at this point. In other words, if a function is differentiable at a certain point, it must be continuous at that point. Derivable functions must be continuous and discontinuous functions must be non-differentiable.