Inequality is an important concept in mathematics, and it is a symbolic inequality relationship. Used to indicate the size relationship between numerical values, such as greater than, less than, greater than or equal to, less than or equal to, etc. Inequality can be used to solve many practical problems, such as economy, engineering, natural science, social science and other fields. For example, in the economic field, inequality can be used to describe the relationship between consumption and income; In the engineering field, it can be used to describe the relationship between work efficiency and resource consumption. Therefore, mastering the concept and application of inequality is of great significance to students and people engaged in related fields.

The solution of inequality refers to the set of solutions obtained when solving the unknown in inequality. The method of solving inequality is slightly different from that of solving equation. In the process of solving inequality, we need to pay attention to the direction of inequality, because it will affect the correctness of the result. In addition, the process of solving inequality sometimes involves some special situations, such as absolute inequality and square inequality. By learning these special inequalities, we can better solve practical problems.

In the application of inequality, we often need to use various inequality theorems to solve problems. For example, Cauchy-Schwartz inequality can be used to solve the inner product between two vectors; Zibyshev inequality can be used to solve the variance of a set of data. In addition, there are Bernoulli inequality, Cauchy inequality, weighted average inequality and so on. These inequality theorems are very important in advanced mathematics. They can not only help us better understand the concept and application of inequality, but also help us solve practical problems. So mastering these inequality theorems is the key to learning inequalities well.