Mathematics is very abstract and complex in the eyes of many people, but there are often very harmonious and natural laws behind these complex phenomena. If we can better understand and master these laws, our understanding of mathematics will be deeper. Many people who are obsessed with mathematics are attracted by this feature of mathematics. Vieta's theorem well reflects this characteristic of mathematics.

Vieta's theorem was named after the French mathematician Veda in the 6th century/kloc-0. Vieta theorem reflects the basic characteristics of polynomial root problem by revealing the relationship between polynomial root and coefficient, and is one of the key theorems in polynomial theory. In middle school, students are familiar with Vieta theorem of quadratic polynomial, that is, for ax2+bx+c(a≠0), if its two roots are x 1 and x2, then x 1+x2=-ba, X65438+X2 = CA. Using this relationship, we can directly express the values of some symmetric formulas about x 1 and x2 with coefficients without requiring roots, such as:

1x1+1x2 = x1+x2x1x2 =-baca =-BC, etc.

David has also made many achievements in trigonometry and algebra, especially in the establishment of algebraic symbol system.