摘要
Abstract
In order to calculate the limit of a function at a point, judge continuity and derivabilityof the func-tion at a point and calculate the discontinuity point and its classification, limit should be calculated first. All of these have a common problem, that is, when to calculate the limit and when not to. As for such doubts, the key to solve these problems is all of these issues need to use a key point of knowledge, that is, scope of the right and left limit. In view of the knowledge point and the key,several problems should be paid attention to, which will be described in the paper.关键词
极限/连续/可导性/适用范围Key words
limit/continuity/derivability/scope分类
社会科学
