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

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

3???sn

4?????98?

5?????????

?????????????1?30????? ?,30?,?????5.6??????????,???21???6.4??

??????,30????????????10??????11????,????????????5.6????????????,????????10????,?????5????????,????????????????10?4???????????,??3.2?4.3????,???

??????????,???,??,?????????

???,30??????????10???11??????5.2?????????(???????) ???????????:??