Take the derivative first, then make the derivative function equal to zero, find the value of x, then determine the domain and draw a table. Finally, find the extreme value.

Note: Extreme value refers to substituting the x value in the derivative function into the original function.

Extended data:

Solve the extreme value of a function:

The goal of mathematical optimization is to find the maximum and minimum in the whole function domain. If the function is continuous in the closed interval, there are maxima and minima in the whole region through the extreme value theorem.

In addition, the maximum (or minimum) on the whole domain must be a local maximum (or minimum) within the domain, or it must be located on the boundary of the domain.

Therefore, the way to find the maximum (or minimum) in the whole domain is to look at all the local maximum (or minimum) inside, and also look at the maximum (or minimum) of points on the boundary, and take the maximum or minimum.

Extreme values are defined as follows:

If the function f (x) is defined in a neighborhood d of x, and all points in d except x have f(x)

Similarly, if all points of d have f (x) >; f(x？ ), just call f(x? ) is the minimum value of the function f(x)

Baidu Encyclopedia: Ultimate Value