???9??25? 9?????25?,?????????,????????:????????????,???????????????????????

????????,????????????,????????9???????????????2?????,????“????????????”,???????????????????????????,???“?????????”????????????,?????????????,??????????,??????????????,?????????????????,??,???

??????????:???????????????????? “?????????”_????

?? ???????????????????

????:1??????????:????vx

2?????

3??????

4???????

5???????

???9??25? 9?????25?,?????????,????????:????????????,???????????????????????

????????,????????????,????????9???????????????2?????,????“????????????”,???????????????????????????,???“?????????”????????????,?????????????,??????????,??????????????,?????????????????,??,???

??????????:????????????????????