4-2 is the easiest to remember: 1. Several special matrices, such as symmetric transformation, telescopic transformation, etc. 2. Inverse matrix, with formula, write it down and add an exercise in less than 5 minutes; 3. eigenvectors and eigenvectors can be mastered in less than 10 minutes as long as you have good notes. The landlord remembers to practice occasionally.

4-4 The requirements of Fujian Province are not high, and the key points are: 1. Comparison between polar coordinates and plane rectangular coordinates; 2. Parameter equation, focusing on calculation, sometimes combining with function test points to investigate the maximum value; 3. Transform polar coordinates into rectangular coordinates and solve several geometric problems. The focus is on transformation, and the rest is basic skills.

4-5 inequality is more difficult, so we should focus on the main points. If these are not admitted, the landlord will accept his fate. (This probability is very small): 1. Absolute inequality, mainly (1) zero division method (2) the geometric meaning of absolute inequality is the distance between points on the number axis (3) several properties of absolute inequality, mainly solving the maximum problem; 2. Three special inequalities, (1) basic inequalities, including two and three Cauchy inequalities, are often used to solve the maximum problem (3) rank inequality.

In fact, there is an inequality, but it has hardly appeared in recent years, and your teacher may not say much.