Qinsheng inequality has many functions, especially in proving inequality. It is often easier to prove with Qin Sheng inequality than with other general theories.
The concavity and convexity of function has no specific requirements in senior high school mathematics, but it is actually an important property of the function learned in higher mathematics. The inequality between piano students and students often appears in high school math exercises or college entrance examination questions, which also shows that the principle of college entrance examination proposition comes from textbooks and is higher than textbooks, and also reflects the selection function of transporting outstanding talents for colleges and universities.
Have nature
Inequality 1: The same number (or formula) is added (or subtracted) on both sides of the inequality at the same time, and the direction of the inequality remains unchanged.
Inequality property 2: both sides of the inequality are multiplied (or divided) by the same positive number at the same time, and the direction of the inequality remains unchanged.
Inequality property 3: both sides of inequality are multiplied (or divided) by the same negative number at the same time, and the direction of inequality changes.
Summary: when the product of two positive numbers is constant, their sum has a minimum value; When the sum of two positive numbers is constant, their product has a maximum value.