zWhat does it mean when f''(x) < 0, = 0, > 0? And how do you find points of inflection? f’’(x) < 0 ⇒ concave ⇒ maximum point. f’’(x) = 0 ⇒ MAYBE a point of inflection YET point of inflection ⇒ f’’(x) = 0. To make sure you have a point, check for a change in concavity either side of the point (if so, is a point of inflection) and consider points where the f''(x) is undefined. f’’(x) > 0 ⇒ convex ⇒ minimum point.