In the postgraduate entrance examination, candidates can choose mathematics and chemistry according to their own learning foundation and the need of volunteering for research work. Compared with chemistry, mathematics has fewer knowledge points but is more flexible. The grade of this course is 150, accounting for 1/4 of the total score. Mathematics is a basic subject used in all kinds of research, and it is an indispensable knowledge system in the process of preliminary experimental design, scheme selection, data analysis, result inference, model establishment and paper completion. In addition, learning mathematics can exercise logical reasoning ability, make people form a rigorous and abstract way of thinking, and is conducive to thinking and solving problems.

Mathematics is a science that studies quantitative relations and spatial forms, with strict symbol system, unique formula structure and vivid image language. It has three remarkable characteristics: high abstraction, strict logic and wide application. (1) The abstraction of mathematics abandons the concrete content of the object, and only retains the quantitative relationship and spatial form. In the eyes of mathematicians, there is no difference between five stones, five mountains, five golden flowers and five poisonous snakes. Mathematicians only care about "five" Concepts such as "set", "equation" and "function" are all products of abstract thinking. (2) Many mathematical results are difficult to find realistic prototypes with intuitive significance, and are often studied under ideal conditions. The correctness of mathematical operation, mathematical reasoning, mathematical proof, mathematical theory, etc. It can't be tested by repeatable experiments like natural science, but can only be realized by strict logical methods. For example, the derivation of the root formula of a quadratic equation in one variable, the determination of the positional relationship between two straight lines, the derivation of an infinitesimal quantity and so on. (3) As a tool or means, mathematics is applied to almost any science and technology and all social fields. Mathematicization of various sciences is a major trend in the development of modern science. In learning, we should pay attention to the practical application of mathematics, such as the geometric meaning of calculus, such as how to analyze experimental data by mathematical methods, establish models and so on.