The existence of a zero point in the derivative means that the function has an extreme value at that point.

For example, f'(2)=0, which means that f(x) has an extreme value when x=2.

There is something wrong with the above answer.

It can only be said that it may be an extreme point, such as f (x) = x 3.

F'(0)=0, but x=0 is not the extreme point of the function.

On the other hand, if the function is the extreme point of an x value, the derivative must be 0.