Existence conditions:
prerequisite
Let the function f(x) have a second-order continuous derivative in a certain neighborhood, if it is the inflection point of the curve, otherwise it will not hold.
The first sufficient condition:
According to the definition of inflection point directly, the first sufficient condition for the existence of inflection point can be obtained.
Let the function f(x) have a second-order continuous derivative in a certain neighborhood, and the signs on both sides are different, which is an inflection point of the curve y=f(x); The same symbol on both sides is not the inflection point of the curve.
Inflection point calculation