Let the domain of definition of function f (x) be r, and there are two propositions as follows: 1. If there is a constant m such that any x ∈ R, there is f (x) 2. If there exists x0 ∈ R, such that for any x ∈ R, and X is not equal to x0, f (x)

Let the domain of definition of function f (x) be r, and there are two propositions as follows: 1. If there is a constant m such that any x ∈ R, there is f (x) 2. If there exists x0 ∈ R, such that for any x ∈ R, and X is not equal to x0, f (x)

2 means that the function f (x) has a maximum f (x0) of one,
But the maximum point of F (x) is not unique
For example, y = SiNx, x0 = π / 2 are the maximum points, but there are infinitely many maximum points, x = 2K π + π / 2, K ∈ Z
3 is correct, ensure that f (x0) is the maximum, do not exclude other maximum points