????:1???????:?????????

2??????????????

3???????????

4?????

5???????sn

?????9??21? (? ?)??????????????????9???21???18?51?????????4.5??,???

?,9????21?18?51??(?24.30????,????121.60??)????????????4.5?????,?20???

?????,??????????200??5????????4???????343???????????,????2024??4?3??????7.3???

???????,???????????????????????????????????,?,???,???(?) ??????:????