Engineering, agronomy, economics and other majors are one of the main categories for postgraduate entrance examination. In some professional examinations, mathematics is an important subject, and candidates need to master the basic knowledge of mathematics and the ability to solve problems. Advanced mathematics, linear algebra, probability theory and other mathematical knowledge are essential in the preparation process of postgraduate entrance examination. Mastering a solid mathematical foundation and being able to skillfully use mathematical tools and methods to solve problems is very important for successfully passing the exam and doing a good job in professional study.