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

2????????

3????????

4????????????

5????????

????11????????????23????(? ????????)11????????23?????,??????,????????????,???????????????????

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

????????????,??,?????????,??????????????,????????????,???????????,????;??????????????????,???????????????,??,????????????????????,????????

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