1, the winning book gives a detailed explanation of Dirichlet's principle in high school mathematics, including the scope of application, proof methods and various typical problems. , and provides a large number of examples and exercises, which is helpful for readers to fully grasp this knowledge point and carry out consolidation exercises.

2. Denggao book gives a comprehensive and in-depth explanation of the basic knowledge points in high school physics, including the basic concepts of physics, kinematics, mechanics, electromagnetism and so on. They are presented in the form of pictures and texts, which helps readers to better understand and digest knowledge points.