If , then the graph of  may have inflection point at  or may not have inflection point.

If the graph have a critical point at , then the inflection point at  is neglected.

Consider the example function .

Apply first derivative on each side  with respect to .

Find the critical values by equating first derivative to zero.

The function has critical point at .

Apply second derivative on each side with respect to .

Find the inflection points by equating second derivative to zero.

So the inflection point at  is neglected, since it has critical point at . 

So the function is false.