Ye Li (1 192—1279), who lives between Xin and Bu (now Xin and Hun County, Shaanxi Province), wrote books and made statements. 1265 was called a bachelor's degree in imperial academy in the Yuan Dynasty. A few months later, due to illness, he returned to his hometown and bought a field in Fenglongshan, Yuanshi County (now Yuanshi County, Hebei Province) to give lectures until the end of the year.
Ye Li has not participated in many activities in his life, but he is by no means an old-school Confucian scholar who respects Confucianism and believes in the past and doubts the present. He advocated the rule of law and dared to point out the root causes of the backwardness of political affairs at that time. Ideologically, he has simple materialism.
Because of this, Ye Li was able to sum up, popularize and improve mathematical science with confidence, regardless of fame, not afraid of sarcasm, and made outstanding contributions to the development of ancient mathematics in China.
Ye Li's Mathematical Contribution
Ye Li got rid of the bondage of geometric thinking and made four progress in equation theory:
First, he changed the traditional concept that the constant term is regarded as a positive number, and the constant term can be a positive number or a negative number, instead of sticking to its geometric meaning.
Second, Ye Li has been able to skillfully list higher-order equations by using celestial technology. Here, the unknown is purely algebraic, the quadratic equation does not represent the area, and the cubic equation does not represent the volume.
Ye Li has completely solved the problem of fractional equation, and he has learned how to change fractional equation into integral equation by multiplying both sides of the equation by an algebraic expression.
Fourthly, Ye Li learned how to reduce the number of equations by pure algebra. When each term of the equation contains the common factor xn(n is a positive integer), Ye Li makes the lowest degree term a real number, and all other terms reduce this degree. q