Generally, it will be more or less tested in the college entrance examination in various provinces and cities, and it is easier to appear in the form of multiple-choice questions or fill-in-the-blank questions. Basic inequalities will also be frequently used in the application questions of big questions (generally, the same answer can be obtained by derivative, but using basic inequalities will make the calculation easier).

When proving inequality by causal deduction, the inequality to be proved is derived from the known inequality and the conditions of the problem by using the nature and appropriate deformation of inequality. This method is also called direct deduction or causal deduction.

When proving inequality, we should start from the proposition to be proved and find the sufficient conditions for its establishment. Because it is not convenient to write proof with "analytical method", sometimes we can find a way to prove the problem with analytical method and then express it with "comprehensive method".