ÌâÄ¿ÄÚÈÝ
£¨08ÄêÁúÑÒÒ»Öгå´ÌÎÄ£©£¨·Ö£©ÒÑ֪˫ÇúÏßCµÄÖÐÐÄÔÚԵ㣬½¹µãÔÚxÖáÉÏ£¬ÓÒ×¼ÏßΪһÌõ½¥½üÏߵķ½³ÌÊǹýË«ÇúÏßCµÄÓÒ½¹µãF2µÄÒ»ÌõÏÒ½»Ë«ÇúÏßÓÒÖ§ÓÚP¡¢QÁ½µã£¬RÊÇÏÒPQµÄÖеã.
£¨1£©ÇóË«ÇúÏßCµÄ·½³Ì£»
£¨2£©ÈôA¡¢B·Ö±ðÊÇË«ÇúCÉÏÁ½Ìõ½¥½üÏßÉϵĶ¯µã£¬ÇÒ2|AB|=|F1F2|£¬ÇóÏ߶ÎABµÄÖеãMµÄ¼£·½³Ì£¬²¢ËµÃ÷¸Ã¹ì¼£ÊÇʲôÇúÏß¡£
£¨3£©ÈôÔÚË«ÇúÏßÓÒ×¼ÏßLµÄ×ó²àÄÜ×÷³öÖ±Ïßm:x=a£¬Ê¹µãRÔÚÖ±ÏßmÉϵÄÉäÓ°SÂú×㣬µ±µãPÔÚÇúÏßCÉÏÔ˶¯Ê±£¬ÇóaµÄÈ¡Öµ·¶Î§.
½âÎö£º£¨1£©ÉèË«ÇúÏßCµÄ·½³ÌΪ£¬
ÔòËüµÄÓÒ×¼Ïß·½³ÌΪ
ÒÑÖªµÃ=1£¬Ôò=1£¬ËùÒÔËùÇóË«ÇúÏßCµÄ·½³ÌÊÇ¡¡¡¡¡¡4·Ö
£¨2£©ÉèA£¨x1,x2£©¡¢B£¨x1¡¢x2£©¡¢M£¨x,y£©
Ôò
ÒòΪ˫ÇúÏßCµÄ½üÏß·½³ÌΪ
ËùÒÔ
¹Ê
ÓÖ2|AB|=ËùÒÔ|AB|=
¼´ ¡¡¡¡¡¡7·Ö
¼´
¼´ ËùÒÔ¡¡¡¡¡¡7·Ö
ËùÒÔµãMµÄ¹ì¼£ÖÐÐÄÔÚԵ㣬½¹µãÔÚyÖáÉÏ£¬³¤Ö᳤Ϊ6£¬¶ÌÖ᳤Ϊ2µÄÍÖÔ²
£¨3£©ÒòΪµãRÔÚÖ±ÏßmÉϵÄÉäÓ°SÂú×ã
ËùÒÔPS¡ÍQS£¬¼´¡÷PSQÊÇÖ±½ÇÈý½ÇÐÎ.
ËùÒÔµãRµ½Ö±Ïßm:x=µÄ¾àÀëΪ|RS|=
¼´¡¡¡¡¡¡¡¡¢Ù
ÓÖ¡¡¡¡¡¡9·Ö
ËùÒÔ|PQ|=|PF2|+|F2Q|=2£¨xP+xQ£1£©=4xR£2¡¡¡¡¡¡¡¡¢Ú
½«¢Ú´úÈë¢Ù£¬µÃ¡¡¡¡¡¡10·Ö
ÓÖP¡¢QÊǹýÓÒ½¹µãF2µÄÒ»ÌõÏÒ£¬ÇÒP¡¢Q¾ùÔÚË«ÇúÏßCµÄÓÒÖ§ÉÏ£¬RÊÇÏÒPQµÄÖеã.ËùÒÔ
¹ÊËùÇóaµÄÈ¡Öµ·¶Î§ÊÇa¡Ü£1. ¡¡¡¡¡¡12·Ö