Question

(18·Ö)ÈçͼËùʾ£¬ABCDÊDZ߳¤ÎªLµÄÕý·½ÐΣ¬ÔÚÆäÖеÄÊʵ±ÇøÓòÄÚÓÐÔÈÇ¿´Å³¡£¬´Å³¡·½Ïò´¹Ö±Ö½ÃæÏòÀï¡£ÖÊÁ¿Îªm¡¢µçºÉÁ¿ÎªqµÄÁ£×ÓÒÔ´óСΪvµÄËٶȴ¹Ö±BC±ß´ÓCµãÉäÈëÕý·½ÐÎÇøÓò£¬Ëù¾­¹ýµÄÇøÓò¶¼Óдų¡£¬×îºó´ÓAµãÉä³ö´Å³¡¡£²»¼ÆÁ£×ÓÖØÁ¦¡£Çó£º

£¨1£©ÔÈÇ¿´Å³¡µÄ´Å¸ÐӦǿ¶ÈBµÄ´óС£¿

£¨2£©ÈôÍêÈ«ÏàͬµÄÁ£×ÓÒÔÏàͬµÄËٶȴÓBCµÄÖеãO´¹Ö±BC±ßÉäÈëÕý·½ÐÎÇøÓò£¬ÔÚµ½´ïPµãÇ°£¬Ëù¾­¹ýµÄÇøÓòûÓдų¡£¬´ÓPµã¿ªÊ¼£¬Ëù¾­¹ýµÄÇøÓò¶¼Óдų¡£¬×îºó´ÓAµãÉä³ö´Å³¡¡£ÔòPµãµ½BC±ßµÄ¾àÀëx£½?

 

Answer 1

£¨1£©B£½

£¨2£©x£½

½âÎö:£¨1£©Á£×Ó´¹Ö±BC±ß´ÓCµãÉäÈëÕý·½ÐÎÇøÓò£¬×îºó´ÓAµãÉä³ö´Å³¡£¬Ô²»¡CEAÊÇÔ˶¯¹ì¼££¬ÓÉÓÚÔ²ÐÄÒ»¶¨ÔÚCB»òCBµÄÑÓ³¤ÏßÉÏ£¬Ò²Ò»¶¨ÔÚA¡¢CÁ¬ÏßµÄÖд¹ÏßÉÏ£¬ËùÒÔBµãÊÇÔ²ÐÄ£¬ÉèÔ²»¡µÄ°ë¾¶Îªr£¬Á£×ÓÊܵ½µÄÂåÂ××ÈÁ¦Îª f£¬Ôò

r£½L                                   ¡­¡­¡­¡­¡­¡­£¨2·Ö£©

f£½qvB                                 ¡­¡­¡­¡­¡­¡­£¨2·Ö£©

¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉf£½               ¡­¡­¡­¡­¡­¡­£¨2·Ö£©

½âµÃB£½                           ¡­¡­¡­¡­¡­¡­£¨2·Ö£©

£¨2£©Á£×Ó´ÓBCµÄÖеãO´¹Ö±BC±ßÉäÈëÕý·½ÐÎÇøÓò£¬´ÓPµã¿ªÊ¼£¬×öÔÈËÙÔ²ÖÜÔ˶¯£¬×îºó´ÓAµãÉä³ö´Å³¡£¬Ô²»¡PFAÊÇÔ˶¯¹ì¼££¬°ë¾¶ÈÔȻΪr£¬ÉèÔ²ÐÄΪO₁£¬ÔÚ¡÷APO₁ÖУ¬ÓÐ

PO₁£½r           ¡­¡­¡­¡­¡­¡­£¨1·Ö£©

AO₁£½r           ¡­¡­¡­¡­¡­¡­£¨1·Ö£©

ÓÉÓÚPP₁£½     ¡­¡­¡­¡­¡­¡­£¨1·Ö£©

ËùÒÔP₁O₁£½£¬¼´AP₁ÊÇPO₁µÄÖд¹Ïߣ¬ËùÒÔ

AP£½AO₁£½L       ¡­¡­¡­¡­¡­¡­£¨2·Ö£©

AP₁£½AB£­P₁B£½L£­x   ¡­¡­¡­¡­£¨1·Ö£©

ÔÚ¡÷APP₁ÖУ¬ÓÐ

(AP)²£½(AP₁)²£«(PP₁)²   ¡­¡­¡­¡­£¨2·Ö£©

¼´

½âµÃx£½      ¡­¡­¡­¡­£¨2·Ö£©