[课后练习-1-ans.pdf](https://github.com/user-attachments/files/17827234/-1-ans.pdf) [课后练习-2-ans.pdf](https://github.com/user-attachments/files/17827235/-2-ans.pdf) [课后练习-3-ans.pdf](https://github.com/user-attachments/files/17827236/-3-ans.pdf)
