We will further explore and refine the method of the previous section for deciding whether there is a local maximum or minimum at a critical point. Recall that {{CMD_467}} {{CMD_468}} If {{MATH_469}} on an interval, then {{MATH_470}} is increasing on that interval. {{CMD_471}} If {{MATH_472}} on an interval, then {{MATH_473}} is decreasing on that interval. {{CMD_474}}