The classification discussion in mathematics should focus on the size of unknown constants. Many high school students will have a taken-for-granted problem when doing math problems. For example, for some unknown constants in the topic, we should fully consider their possible values in the process of solving problems (there are several key points, that is, the positive and negative of this constant, or the relationship with 1 or-1 size, and sometimes students will take it for granted that this constant is positive), while in some curve equations, some students just take it for granted and directly open the root sign, so they don't consider its positive and negative at all. There are some typical mistakes. For example, if you want to put an x under the root sign, you should consider the positive and negative of this number. For example, x times the root sign (1+ 1/x squared), and you want to multiply x by it. If x is negative, there should be a negative sign outside when you put it in. . This seems simple, but it is easy to be ignored in the process of doing the problem, which will lead to mistakes.

In fact, for the classification problem, we should pay more attention when doing the problem, and don't take it for granted when considering the problem. I can only think more. At first, don't be afraid of trouble. You can discuss all the useful and useless things in categories. After a while, you will probably know how to classify.

These are my own feelings. You can ask me any other math questions.