ÌâÄ¿ÄÚÈÝ
Èçͼ£¬Ä³ÈËÔÚÒ»¶°¸ß²ã½¨Öþ¶¥²¿C´¦²âµÃɽÆÂƽÅA´¦µÄ¸©½ÇΪ60¡ã£¬ÓÖ²âµÃɽÆÂÉÏÒ»¿ÃСÊ÷Ê÷¸ÉÓëÆÂÃæ½»½çP´¦µÄ¸©½ÇΪ45¡ã£¬ÒÑÖªOA=50Ã×£¬É½ÆÂƶÈΪ
£¨¼´tan¡ÏPAB=
£¬ÆäÖÐPB¡ÍAB£©£¬ÇÒO¡¢A¡¢BÔÚͬһÌõÖ±ÏßÉÏ£®
£¨1£©Çó´Ë¸ß²ã½¨ÖþµÄ¸ß¶ÈOC£»
£¨2£©ÇóƽÅA´¦µ½Ð¡Ê÷Ê÷¸ÉÓëÆÂÃæ½»½çP´¦µÄÆÂÃæ¾àÀëAPµÄ³¤¶È£®£¨È˵ĸ߶ȼ°²âÁ¿ÒÇÆ÷¸ß¶ÈºöÂÔ²»¼Æ£¬½á¹û±£Áô¸ùºÅÐÎʽ£©
1 |
2 |
1 |
2 |
£¨1£©Çó´Ë¸ß²ã½¨ÖþµÄ¸ß¶ÈOC£»
£¨2£©ÇóƽÅA´¦µ½Ð¡Ê÷Ê÷¸ÉÓëÆÂÃæ½»½çP´¦µÄÆÂÃæ¾àÀëAPµÄ³¤¶È£®£¨È˵ĸ߶ȼ°²âÁ¿ÒÇÆ÷¸ß¶ÈºöÂÔ²»¼Æ£¬½á¹û±£Áô¸ùºÅÐÎʽ£©
£¨1£©Rt¡÷OACÖУ¬¡ÏOAC=60¡ã£¬OA=50Ã×£¬
¡àOC=OA•tan60¡ã=50
Ã×£®
´ð£º´Ë¸ß²ã½¨ÖþµÄ¸ß¶ÈOCΪ50
Ã×£®
£¨2£©¹ýP×÷PM¡ÍOCÓÚM£®
Rt¡÷PMCÖУ¬¡ÏCPM=45¡ã£¬ÔòPM=CM£®
Rt¡÷PBAÖУ¬tan¡ÏPAB=
£®
ÉèPB=x£¬ÔòAB=2x£®
CM=OC-OM=50
-x£¬PM=OA+AB=50+2x£®
¡à50
-x=50+2x£¬
¼´x=
£®
¡ßAB=2x£¬AP=
=
=
x£¬
¡àAB=
£¨Ã×£©£¬
AP=
£¨Ã×£©£®
´ð£ºÆ½ÅA´¦µ½Ð¡Ê÷Ê÷¸ÉÓëÆÂÃæ½»½çP´¦µÄÆÂÃæ¾àÀëAPµÄ³¤¶ÈΪ
£¨Ã×£©£®
¡àOC=OA•tan60¡ã=50
3 |
´ð£º´Ë¸ß²ã½¨ÖþµÄ¸ß¶ÈOCΪ50
3 |
£¨2£©¹ýP×÷PM¡ÍOCÓÚM£®
Rt¡÷PMCÖУ¬¡ÏCPM=45¡ã£¬ÔòPM=CM£®
Rt¡÷PBAÖУ¬tan¡ÏPAB=
1 |
2 |
ÉèPB=x£¬ÔòAB=2x£®
CM=OC-OM=50
3 |
¡à50
3 |
¼´x=
50
| ||
3 |
¡ßAB=2x£¬AP=
AB2+PB2 |
x2+(2x)2 |
5 |
¡àAB=
100
| ||
3 |
AP=
50
| ||||
3 |
´ð£ºÆ½ÅA´¦µ½Ð¡Ê÷Ê÷¸ÉÓëÆÂÃæ½»½çP´¦µÄÆÂÃæ¾àÀëAPµÄ³¤¶ÈΪ
50
| ||||
3 |
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿