- Let $f$ be a differentiable function. If the point c is a critical number, then either it is a local maximum, or local minimum, or an inflection point. $T/F$ ?
If c is a critical point then f'(c)=0 or undefined. So it may local maximum and local minimum.
If f '(c)=∞ then c is inflection point at the same time and if f '(c)=0 it may inflection point again.
But i can't find instance disproves this thesis.