ÌâÄ¿ÄÚÈÝ

19£®É躯Êýy1=£¨x-k£©2+kºÍy2=£¨x+k£©2-kµÄͼÏóÏཻÓÚµãA£¬º¯Êýy1£¬y2µÄͼÏóµÄ¶¥µã·Ö±ðΪBºÍC£®
£¨1£©»­³öµ±k=0£¬1ʱ£¬º¯Êýy1£¬y2ÔÚÖ±½Ç×ø±êϵÖÐͼÏó£»
£¨2£©¹Û²ì£¨1£©ÖÐËù»­º¯ÊýͼÏóµÄ¶¥µãλÖ㬷¢ÏÖËüÃǾù·Ö²¼ÔÚij¸öº¯ÊýµÄͼÏóÉÏ£¬Çëд³öÕâ¸öº¯ÊýµÄ½âÎöʽ£¬²¢ËµÃ÷ÀíÓÉ£»
£¨3£©ÉèA£¨x£¬y£©£¬ÇóÖ¤£ºxÊÇÓëkÎ޹صij£Êý£¬²¢ÇóyµÄ×îСֵ£»
£¨4£©ÉèÖ±Ïßl£ºy=ax+1µÄͼÏó·Ö±ðÓ뺯Êýy1£¬y2µÄͼÏó½»ÓÚA£¬BºÍC£¬D£®ÈôAB=CD£¬Ð´³öËùÓÐʵÊýa£®£¨Ö±½Óд³öaµÄÖµ¼´¿É£¬²»ÒªÇóдÀíÓÉ£©

·ÖÎö £¨1£©k=0ʱ£¬º¯Êýy1=y2=x2£»k=1ʱ£¬º¯Êýy1=£¨x-1£©2+1£¬y2=£¨x+1£©2-1£¬¸ù¾Ý¶þ´Îº¯ÊýµÄͼÏóÓëÐÔÖʷֱ𻭳öËüÃǵÄͼÏó¼´¿É£»
£¨2£©¸ù¾Ý¶þ´Îº¯ÊýµÄÐÔÖÊ·Ö±ðÇó³ö£¨1£©ÖÐËù»­º¯ÊýͼÏóµÄ¶¥µã×ø±ê£¬½áºÏº¯ÊýͼÏ󣬷¢ÏÖ¶¥µãÔÚÖ±Ïßy=xµÄͼÏóÉÏ£»
£¨3£©½«y1=£¨x-k£©2+k´úÈëy2=£¨x+k£©2-k£¬Çó³öxµÄֵΪ³£Êý£¬¼´¿ÉÖ¤Ã÷xÊÇÓëkÎ޹صij£Êý£¬ÔÙÇó³öyµÄ×îСֵ£»
£¨4£©ÏȽ«y=ax+1´úÈëy1=£¨x-k£©2+k£¬ÕûÀíµÃµ½x2-£¨2k+a£©x+k2+k-1=0£¬ÓɸùÓëϵÊýµÄ¹ØÏµµÃ³öAB2=£¨1+a2£©£¨4ka+a2-4k+4£©£¬Í¬ÀíµÃµ½CD2=£¨1+a2£©£¨-4ka+a2+4k+4£©£¬¸ù¾ÝAB=CDµÃ³ö·½³Ì£¨1+a2£©£¨4ka+a2-4k+4£©=£¨1+a2£©£¨-4ka+a2+4k+4£©£¬½â·½³Ì¼´¿ÉÇó³öʵÊýaµÄÖµ£®

½â´ð ½â£º£¨1£©ÈçͼËùʾ£»


£¨2£©º¯Êýy1=y2=x2µÄ¶¥µãΪ£¨0£¬0£©£¬
º¯Êýy1=£¨x-1£©2+1µÄ¶¥µãΪ£¨1£¬1£©£¬
º¯Êýy2=£¨x+1£©2-1µÄ¶¥µãΪ£¨-1£¬-1£©£¬
ËüÃǶ¼ÔÚÖ±Ïßy=xµÄͼÏóÉÏ£¬ÒòΪËüÃǵÄ×ø±ê¾ùÂú×ã½âÎöʽy=x£»

£¨3£©½«y1=£¨x-k£©2+k´úÈëy2=£¨x+k£©2-k£¬
µÃ£¨x-k£©2+k=£¨x+k£©2-k£¬
ÕûÀíµÃ4kx=2k£¬
¡ßº¯Êýy1=£¨x-k£©2+kºÍy2=£¨x+k£©2-kµÄͼÏóÏཻÓÚµãA£¬
¡àk¡Ù0£¬
½âµÃx=$\frac{1}{2}$£¬
¡àxÊÇÓëkÎ޹صij£Êý£»
´Ëʱy=£¨$\frac{1}{2}$+k£©2-k=k2+$\frac{1}{4}$¡Ý$\frac{1}{4}$£¬¼´yµÄ×îСֵΪ$\frac{1}{4}$£»

£¨4£©½«y=ax+1´úÈëy1=£¨x-k£©2+k£¬
µÃax+1=£¨x-k£©2+k£¬
ÕûÀíµÃx2-£¨2k+a£©x+k2+k-1=0£¬
ÉèA£¨x1£¬y1£©£¬B£¨x2£¬y2£©£¬Ôòy1=ax1+1£¬y2=ax2+1£¬
ËùÒÔAB2=£¨x2-x1£©2+£¨y2-y1£©2=£¨1+a2£©£¨x2-x1£©2£¬
¡ß£¨x2-x1£©2=£¨x2+x1£©2-4x2•x1=£¨2k+a£©2-4£¨k2+k-1£©=4ka+a2-4k+4£¬
¡àAB2=£¨1+a2£©£¨4ka+a2-4k+4£©£¬
ͬÀíµÃµ½CD2=£¨1+a2£©£¨-4ka+a2+4k+4£©£¬
¡ßAB=CD£¬
¡à£¨1+a2£©£¨4ka+a2-4k+4£©=£¨1+a2£©£¨-4ka+a2+4k+4£©£¬
¡à4ka+a2-4k+4=-4ka+a2+4k+4£¬
¡à8ka=8k£¬
¡ßk¡Ù0£¬
¡àa=1£®

µãÆÀ ±¾ÌâÊǶþ´Îº¯ÊýµÄ×ÛºÏÌâÐÍ£¬ÆäÖÐÉæ¼°µ½µÄ֪ʶµãÓжþ´Îº¯ÊýµÄͼÏóÓëÐÔÖÊ£¬Á½º¯Êý½»µã×ø±êµÄÇ󷨣¬¶þ´Îº¯ÊýÓëÒ»Ôª¶þ´Î·½³ÌµÄ¹ØÏµ£®ÕýÈ·¼ÆËã³öAB2ÓëCD2Êǽâ¾öµÚ£¨4£©ÎʵĹؼü£®

Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿

Î¥·¨ºÍ²»Á¼ÐÅÏ¢¾Ù±¨µç»°£º027-86699610 ¾Ù±¨ÓÊÏ䣺58377363@163.com

¾«Ó¢¼Ò½ÌÍø