Èçͼ£¬Èý½ÇÐÎABCÊÇÒÔBCΪµ×±ßµÄµÈÑüÈý½ÇÐΣ¬µãA¡¢C·Ö±ðÊÇÒ»´Îº¯Êýy=x+3µÄͼÏóÓëyÖáµÄ½»µã£¬µãBÔÚ¶þ´Îº¯ÊýµÄͼÏóÉÏ£¬ÇҸöþ´Îº¯ÊýͼÏóÉÏ´æÔÚÒ»µãDʹËıßÐÎABCDÄܹ¹³ÉƽÐÐËıßÐΣ®
£¨1£©ÊÔÇób£¬cµÄÖµ£¬²¢Ð´³ö¸Ã¶þ´Îº¯Êý±í´ïʽ£»
£¨2£©¶¯µãP´ÓAµ½D£¬Í¬Ê±¶¯µãQ´ÓCµ½A¶¼ÒÔÿÃë1¸öµ¥Î»µÄËÙ¶ÈÔ˶¯£¬ÎÊ£º
¢Ùµ±PÔ˶¯µ½ºÎ´¦Ê±£¬ÓÐPQ¡ÍAC£¿
¢Úµ±PÔ˶¯µ½ºÎ´¦Ê±£¬ËıßÐÎPDCQµÄÃæ»ý×îС£¿´ËʱËıßÐÎPDCQµÄÃæ»ýÊǶàÉÙ£¿
¡¾´ð°¸¡¿·ÖÎö£º£¨1£©¸ù¾ÝÒ»´Îº¯Êý½âÎöʽÇó³öµãA¡¢µãC×ø±ê£¬ÔÙÓÉ¡÷ABCÊǵÈÑüÈý½ÇÐοÉÇó³öµãB×ø±ê£¬¸ù¾ÝƽÐÐËıßÐεÄÐÔÐÔÖÊÇó³öµãD×ø±ê£¬ÀûÓôý¶¨ÏµÊý·¨¿ÉÇó³öb¡¢cµÄÖµ£¬¼Ì¶øµÃ³ö¶þ´Îº¯Êý±í´ïʽ£®
£¨2£©¢ÙÉèµãPÔ˶¯ÁËtÃëʱ£¬PQ¡ÍAC£¬´ËʱAP=t£¬CQ=t£¬AQ=5-t£¬ÔÙÓÉ¡÷APQ¡×¡÷CAO£¬ÀûÓöÔÓ¦±ß³É±ÈÀý¿ÉÇó³ötµÄÖµ£¬¼Ì¶øÈ·¶¨µãPµÄλÖã»
¢ÚÖ»Ðèʹ¡÷APQµÄÃæ»ý×î´ó£¬¾ÍÄÜÂú×ãËıßÐÎPDCQµÄÃæ»ý×îС£¬Éè¡÷APQµ×±ßAPÉϵĸßΪh£¬×÷QH¡ÍADÓÚµãH£¬ÓÉ¡÷AQH¡×CAO£¬ÀûÓöÔÓ¦±ß³É±ÈÀýµÃ³öhµÄ±í´ïʽ£¬¼Ì¶ø±íʾ³ö¡÷APQµÄÃæ»ý±í´ïʽ£¬ÀûÓÃÅä·½·¨Çó³ö×î´óÖµ£¬¼´¿ÉµÃ³öËıßÐÎPDCQµÄ×îСֵ£¬Ò²¿ÉÈ·¶¨µãPµÄλÖã®
½â´ð£º½â£º£¨1£©ÓÉy=-x+3£¬
Áîx=0£¬µÃy=3£¬ËùÒÔµãA£¨0£¬3£©£»
Áîy=0£¬µÃx=4£¬ËùÒÔµãC£¨4£¬0£©£¬
¡ß¡÷ABCÊÇÒÔBCΪµ×±ßµÄµÈÑüÈý½ÇÐΣ¬
¡àBµã×ø±êΪ£¨-4£¬0£©£¬
ÓÖ¡ßËıßÐÎABCDÊÇƽÐÐËıßÐΣ¬
¡àDµã×ø±êΪ£¨8£¬3£©£¬
½«µãB£¨-4£¬0£©¡¢µãD£¨8£¬3£©´úÈë¶þ´Îº¯Êýy=x2+bx+c£¬¿ÉµÃ£¬
½âµÃ£º£¬
¹Ê¸Ã¶þ´Îº¯Êý½âÎöʽΪ£ºy=x2-x-3£®

£¨2£©¢ÙÉèµãPÔ˶¯ÁËtÃëʱ£¬PQ¡ÍAC£¬´ËʱAP=t£¬CQ=t£¬AQ=5-t£¬
¡ßPQ¡ÍAC£¬
¡à¡÷APQ¡×¡÷CAO£¬
¡à=£¬¼´=£¬
½âµÃ£ºt=£®
¼´µ±µãPÔ˶¯µ½¾àÀëAµã¸öµ¥Î»³¤¶È´¦£¬ÓÐPQ¡ÍAC£®
¢Ú¡ßSËıßÐÎPDCQ+S¡÷APQ=S¡÷ACD£¬ÇÒS¡÷ACD=×8×3=12£¬
¡àµ±¡÷APQµÄÃæ»ý×î´óʱ£¬ËıßÐÎPDCQµÄÃæ»ý×îС£¬
µ±¶¯µãPÔ˶¯tÃëʱ£¬AP=t£¬CQ=t£¬AQ=5-t£¬
Éè¡÷APQµ×±ßAPÉϵĸßΪh£¬×÷QH¡ÍADÓÚµãH£¬ÓÉ¡÷AQH¡×CAO¿ÉµÃ£º=£¬
½âµÃ£ºh=£¨5-t£©£¬
¡àS¡÷APQ=£¨5-t£©=£¨-t2+5t£©=-£¨t-£©2+£¬
¡àµ±t=ʱ£¬S¡÷APQ´ïµ½×î´óÖµ£¬´ËʱSËıßÐÎPDCQ=12-=£¬
¹Êµ±µãPÔ˶¯µ½¾àÀëµãA¸öµ¥Î»´¦Ê±£¬ËıßÐÎPDCQÃæ»ý×îС£¬×îСֵΪ£®
µãÆÀ£º±¾Ì⿼²éÁ˶þ´Îº¯ÊýµÄ×ۺϣ¬Éæ¼°ÁË´ý¶¨ÏµÊý·¨Çóº¯Êý½âÎöʽ¡¢Æ½ÐÐËıßÐεÄÐÔÖÊ¡¢ÏàËÆÈý½ÇÐεÄÅж¨ÓëÐÔÖÊ£¬½â´ð±¾ÌâµÄ¹Ø¼üÊÇÕÒµ½Âú×ãÌâÒâʱµÄÏàËÆÈý½ÇÐΣ¬ÀûÓöÔÓ¦±ß³É±ÈÀýµÄ֪ʶµÃ³öÓйØÏ߶εij¤¶È»ò±í´ïʽ£¬ÄѶȽϴó£®
Á·Ï°²áϵÁдð°¸
Ïà¹ØÏ°Ìâ

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

ÒÑÖª£¬Èçͼ£¬Èý½ÇÐÎABCÊǵÈÑüÖ±½ÇÈý½ÇÐΣ¬¡ÏACB=90¡ã£¬FÊÇABµÄÖе㣬ֱÏßl¾­¹ýµãC£¬·Ö±ð¹ýµãA¡¢B×÷lµÄ´¹Ïߣ¬¼´AD¡ÍCE£¬BE¡ÍCE£¬
£¨1£©Èçͼ1£¬µ±CEλÓÚµãFµÄÓÒ²àʱ£¬ÇóÖ¤£º¡÷ADC¡Õ¡÷CEB£»
£¨2£©Èçͼ2£¬µ±CEλÓÚµãFµÄ×ó²àʱ£¬ÇóÖ¤£ºED=BE-AD£»
£¨3£©Èçͼ3£¬µ±CEÔÚ¡÷ABCµÄÍⲿʱ£¬ÊÔ²ÂÏëED¡¢AD¡¢BEÖ®¼äµÄÊýÁ¿¹Øϵ£¬²¢Ö¤Ã÷ÄãµÄ²ÂÏ룮
¾«Ó¢¼Ò½ÌÍø

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

£¨2013•ºÊÔó£©Èçͼ£¬Èý½ÇÐÎABCÊÇÒÔBCΪµ×±ßµÄµÈÑüÈý½ÇÐΣ¬µãA¡¢C·Ö±ðÊÇÒ»´Îº¯Êýy=-
3
4
x+3µÄͼÏóÓëyÖáµÄ½»µã£¬µãBÔÚ¶þ´Îº¯Êýy=
1
8
x2+bx+c
µÄͼÏóÉÏ£¬ÇҸöþ´Îº¯ÊýͼÏóÉÏ´æÔÚÒ»µãDʹËıßÐÎABCDÄܹ¹³ÉƽÐÐËıßÐΣ®
£¨1£©ÊÔÇób£¬cµÄÖµ£¬²¢Ð´³ö¸Ã¶þ´Îº¯Êý±í´ïʽ£»
£¨2£©¶¯µãP´ÓAµ½D£¬Í¬Ê±¶¯µãQ´ÓCµ½A¶¼ÒÔÿÃë1¸öµ¥Î»µÄËÙ¶ÈÔ˶¯£¬ÎÊ£º
¢Ùµ±PÔ˶¯µ½ºÎ´¦Ê±£¬ÓÐPQ¡ÍAC£¿
¢Úµ±PÔ˶¯µ½ºÎ´¦Ê±£¬ËıßÐÎPDCQµÄÃæ»ý×îС£¿´ËʱËıßÐÎPDCQµÄÃæ»ýÊǶàÉÙ£¿

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

£¨2013•´óÇ죩Èçͼ£¬Èý½ÇÐÎABCÊDZ߳¤Îª1µÄÕýÈý½ÇÐΣ¬
AB
Óë
AC
Ëù¶ÔµÄÔ²ÐĽǾùΪ120¡ã£¬ÔòͼÖÐÒõÓ°²¿·ÖµÄÃæ»ýΪ
3
12
3
12
£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º2013Äê³õÖбÏÒµÉýѧ¿¼ÊÔ£¨É½¶«ºÊÔó¾í£©Êýѧ£¨´ø½âÎö£© ÌâÐÍ£º½â´ðÌâ

Èçͼ£¬Èý½ÇÐÎABCÊÇÒÔBCΪµ×±ßµÄµÈÑüÈý½ÇÐΣ¬µãA¡¢C·Ö±ðÊÇÒ»´Îº¯ÊýµÄͼÏóÓëyÖáµÄ½»µã£¬µãBÔÚ¶þ´Îº¯ÊýµÄͼÏóÉÏ£¬ÇҸöþ´Îº¯ÊýͼÏóÉÏ´æÔÚÒ»µãDʹËıßÐÎABCDÄܹ¹³ÉƽÐÐËıßÐΣ®

£¨1£©ÊÔÇób£¬cµÄÖµ£¬²¢Ð´³ö¸Ã¶þ´Îº¯Êý±í´ïʽ£»
£¨2£©¶¯µãP´ÓAµ½D£¬Í¬Ê±¶¯µãQ´ÓCµ½A¶¼ÒÔÿÃë1¸öµ¥Î»µÄËÙ¶ÈÔ˶¯£¬ÎÊ£º
¢Ùµ±PÔ˶¯µ½ºÎ´¦Ê±£¬ÓÐPQ¡ÍAC£¿
¢Úµ±PÔ˶¯µ½ºÎ´¦Ê±£¬ËıßÐÎPDCQµÄÃæ»ý×îС£¿´ËʱËıßÐÎPDCQµÄÃæ»ýÊǶàÉÙ£¿

²é¿´´ð°¸ºÍ½âÎö>>

ͬ²½Á·Ï°²á´ð°¸