5£®Èçͼ£¬ÒÑÖªÅ×ÎïÏßy=k£¨x+2£©£¨x-4£©£¨kΪ³£Êý£¬ÇÒk£¾0£©ÓëxÖáµÄ½»µãΪA¡¢B£¬ÓëyÖáµÄ½»µãΪC£¬¾­¹ýµãBµÄÖ±Ïßy=-$\frac{1}{2}$x+bÓëÅ×ÎïÏßµÄÁíÒ»¸ö½»µãΪD£®
£¨1£©ÈôµãDµÄºá×ø±êΪx=-4£¬ÇóÕâ¸öÒ»´Îº¯ÊýÓëÅ×ÎïÏߵĽâÎöʽ£»
£¨2£©ÈôÖ±ÏßmƽÐÐÓÚ¸ÃÅ×ÎïÏߵĶԳÆÖᣬ²¢ÇÒ¿ÉÒÔÔÚÏß¶ÎAB¼ä×óÓÒÒÆ¶¯£¬ËüÓëÖ±ÏßBDºÍÅ×ÎïÏß·Ö±ð½»ÓÚµãE¡¢F£¬Çóµ±mÒÆ¶¯µ½Ê²Ã´Î»ÖÃʱ£¬EFµÄÖµ×î´ó£¬×î´óÖµÊǶàÉÙ£¿
£¨3£©ÎÊÔ­Å×ÎïÏßÔÚµÚÒ»ÏóÏÞÊÇ·ñ´æÔÚµãF£¬Ê¹µÃ¡÷APB¡×¡÷ABC£¿Èô´æÔÚ£¬ÇëÖ±½Óд³öÕâʱkµÄÖµ£»Èô²»´æÔÚ£¬Çë˵Ã÷ÀíÓÉ£®

·ÖÎö £¨1£©ÏȽⷽ³Ìk£¨x+2£©£¨x-4£©=0¿ÉµÃA£¨-2£¬0£©£¬B£¨4£¬0£©£¬ÔÙ°ÑBµã×ø±ê´úÈëy=-$\frac{1}{2}$x+bÖÐÇó³öµÃb=2£¬Ôò¿ÉµÃµ½Ò»´Îº¯Êý½âÎöʽΪy=-$\frac{1}{2}$x+2£¬½Ó×ÅÀûÓÃÒ»´Îº¯Êý½âÎöʽȷ¶¨Dµã×ø±ê£¬È»ºó°ÑDµã×ø±ê´úÈë´úÈëy=k£¨x+2£©£¨x-4£©ÖÐÇó³ökµÄÖµ¼´¿ÉµÃµ½µÃÅ×ÎïÏß½âÎöʽ£»
£¨2£©ÀûÓöþ´Îº¯ÊýºÍÒ»´Îº¯ÊýͼÏóÉϵãµÄ×ø±êÌØÕ÷£¬¿ÉÉèF£¨t£¬$\frac{1}{4}$t2-$\frac{1}{2}$t-2£©£¬ÔòE£¨t£¬-$\frac{1}{2}$t+2£©£¬-2¡Üt¡Ü4£¬ÓÚÊǵõ½EF=-$\frac{1}{2}$t+2-£¨$\frac{1}{4}$t2-$\frac{1}{2}$t-2£©=-$\frac{1}{4}$t2+4£¬È»ºó¸ù¾Ý¶þ´Îº¯ÊýµÄÐÔÖÊÇó½â£»
£¨3£©×÷PH¡ÍxÖáÓÚH£¬Èçͼ£¬Ïȱíʾ³öCµã×ø±êΪ£¨0£¬-8k£©£¬ÉèP[n£¬k£¨n+2£©£¨n-4£©]£¬¸ù¾ÝÏàËÆÈý½ÇÐεÄÅж¨·½·¨£¬µ±¡ÏPAB=¡ÏCAB£¬AP£ºAB=AB£ºACʱ£¬¡÷APB¡×¡÷ABC£»ÔÙ¸ù¾ÝÕýÇж¨Ò壬ÔÚRt¡÷APHÖÐÓÐtan¡ÏPAH=$\frac{k£¨n+2£©£¨n-4£©}{n+2}$£¬ÔÚRt¡÷OACÖÐÓÐtan¡ÏOAC=$\frac{8k}{2}$=4k£¬Ôò$\frac{k£¨n+2£©£¨n-4£©}{n+2}$=4k£¬½âµÃn=8£¬ÓÚÊǵõ½P£¨8£¬40k£©£¬½Ó×ÅÀûÓù´¹É¶¨Àí¼ÆËã³öAP=10$\sqrt{16{k}^{2}+1}$£¬AC=2$\sqrt{16{k}^{2}+1}$£¬È»ºóÀûÓÃAP£ºAB=AB£ºACµÃµ½10$\sqrt{16{k}^{2}+1}$•2$\sqrt{16{k}^{2}+1}$=62£¬½âµÃk1=$\frac{\sqrt{5}}{10}$£¬k2=-$\frac{\sqrt{5}}{10}$£¨ÉáÈ¥£©£¬ÓÚÊÇ¿ÉÈ·¶¨Pµã×ø±ê£®

½â´ð ½â£º£¨1£©µ±y=0ʱ£¬k£¨x+2£©£¨x-4£©=0£¬½âµÃx1=-2£¬x2=4£¬ÔòA£¨-2£¬0£©£¬B£¨4£¬0£©£¬
°ÑB£¨4£¬0£©´úÈëy=-$\frac{1}{2}$x+bµÃ-2+b=0£¬½âµÃb=2£¬
ËùÒÔÒ»´Îº¯Êý½âÎöʽΪy=-$\frac{1}{2}$x+2£¬
µ±x=-4ʱ£¬y=-$\frac{1}{2}$x+2=4£¬ÔòDµã×ø±êΪ£¨4£¬4£©£¬
°ÑD£¨-4£¬4£©´úÈëy=k£¨x+2£©£¨x-4£©µÃk•£¨-2£©•£¨-8£©=4£¬½âµÃk=$\frac{1}{4}$£¬
ËùÒÔÅ×ÎïÏß½âÎöʽΪy=$\frac{1}{4}$£¨x+2£©£¨x-4£©£¬¼´y=$\frac{1}{4}$x2-$\frac{1}{2}$x-2£»
£¨2£©ÉèF£¨t£¬$\frac{1}{4}$t2-$\frac{1}{2}$t-2£©£¬ÔòE£¨t£¬-$\frac{1}{2}$t+2£©£¬-2¡Üt¡Ü4£¬
ËùÒÔEF=-$\frac{1}{2}$t+2-£¨$\frac{1}{4}$t2-$\frac{1}{2}$t-2£©=-$\frac{1}{4}$t2+4£¬
ËùÒÔµ±t=0ʱ£¬EF×î´ó£¬×î´óֵΪ4£¬
¼´µ±Ö±ÏßmÒÆ¶¯µ½ÓëyÖáÖØºÏµÄλÖÃʱ£¬EFµÄÖµ×î´ó£¬×î´óÖµÊÇ4£»
£¨3£©´æÔÚ£®
×÷PH¡ÍxÖáÓÚH£¬Èçͼ£¬
µ±x=0ʱ£¬y=k£¨x+2£©£¨x-4£©=-8k£¬ÔòC£¨0£¬-8k£©£¬
ÉèP[n£¬k£¨n+2£©£¨n-4£©]£¬
µ±¡ÏPAB=¡ÏCAB£¬AP£ºAB=AB£ºACʱ£¬¡÷APB¡×¡÷ABC£»
ÔÚRt¡÷APHÖУ¬tan¡ÏPAH=$\frac{k£¨n+2£©£¨n-4£©}{n+2}$£¬
ÔÚRt¡÷OACÖУ¬tan¡ÏOAC=$\frac{8k}{2}$=4k£¬
¡à$\frac{k£¨n+2£©£¨n-4£©}{n+2}$=4k£¬½âµÃn=8£¬ÔòP£¨8£¬40k£©£¬
¡àAP=$\sqrt{P{H}^{2}+A{H}^{2}}$=$\sqrt{£¨40k£©^{2}+1{0}^{2}}$=10$\sqrt{16{k}^{2}+1}$£¬
¶øAC=$\sqrt{O{C}^{2}+O{A}^{2}}$=$\sqrt{£¨8k£©^{2}+{2}^{2}}$=2$\sqrt{16{k}^{2}+1}$£¬
¡ßAP£ºAB=AB£ºAC£¬
¡àAP•AC=AB2£¬
¼´10$\sqrt{16{k}^{2}+1}$•2$\sqrt{16{k}^{2}+1}$=62£¬
¡à5£¨16k2+1£©=9£¬½âµÃk1=$\frac{\sqrt{5}}{10}$£¬k2=-$\frac{\sqrt{5}}{10}$£¨ÉáÈ¥£©£¬
¡àk=4$\sqrt{5}$£¬Pµã×ø±êΪ£¨8£¬4$\sqrt{5}$£©£®

µãÆÀ ±¾Ì⿼²éÁ˶þ´Îº¯ÊýµÄ×ÛºÏÌ⣺ÊìÁ·ÕÆÎÕ¶þ´Îº¯ÊýͼÏóÉϵãµÄ×ø±êÌØÕ÷ºÍ¶þ´Îº¯ÊýµÄÐÔÖÊ£»Áé»îÓ¦ÓÃÏàËÆ±ÈºÍ¹´¹É¶¨Àí¼ÆËãÏàÓ¦Ï߶εij¤£»Àí½â×ø±êÓëͼÐÎÐÔÖÊ£®

Á·Ï°²áϵÁдð°¸
Ïà¹ØÏ°Ìâ

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º2017½ì¹ã¶«Ê¡¹ãÖÝÊоÅÄê¼¶ÏÂѧÆÚ3ÔÂÔ¿¼ÊýѧÊÔ¾í£¨½âÎö°æ£© ÌâÐÍ£ºÅжÏÌâ

ÒÑÖª¶àÏîʽA=.

Çó¡¾½âÎö¡¿
£¨1£©»¯¼ò¶àÏîʽA£» £¨2£©Èô£¬ÇóAµÄÖµ.

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º2017½ì½­ËÕÊ¡ÐìÖÝÊоÅÄê¼¶ÏÂѧÆÚµÚÒ»´Î£¨3Ô£©Ô¿¼ÊýѧÊÔ¾í£¨½âÎö°æ£© ÌâÐÍ£ºµ¥Ñ¡Ìâ

Èôʽ×ÓÔÚʵÊý·¶Î§ÄÚÓÐÒâÒ壬ÔòxµÄȡֵ·¶Î§ÊÇ£¨¡¡¡¡£©

A. x¡Ù1 B. x£¾1 C. x¡Ý1 D. x¡Ü1

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º2016-2017ѧÄê½­Î÷Ê¡ÐÂÓàÊаËÄê¼¶ÏÂѧÆÚµÚÒ»´Î¶Î¿¼ÊýѧÊÔ¾í£¨½âÎö°æ£© ÌâÐÍ£ºÌî¿ÕÌâ

Èçͼ£¬ÔÚÆ½ÐÐËıßÐÎABCDÖУ¬BEƽ·Ö¡ÏABC½»±ßADÓÚE£®ÒÑÖªAB=8£¬BC=10£¬ÔòDE= ______ £®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

1£®ÒÑÖª¡÷ABCºÍ¡÷ADE¶¼ÊǵÈÑüÖ±½ÇÈý½ÇÐΣ¬¡ÏACB=¡ÏADE=90¡ã£¬AC=2$\sqrt{2}$£¬AD=1£¬FÊÇBEµÄÖе㣮Èô½«¡÷ADEÈÆµãAÐýתһÖÜ£¬ÔòÏß¶ÎAF³¤¶ÈµÄȡֵ·¶Î§ÊÇ£¨¡¡¡¡£©
A£®$\frac{4-\sqrt{2}}{2}$¡ÜAF¡Ü$\frac{4+\sqrt{2}}{2}$B£®2¡ÜAF¡Ü3C£®$\frac{4-\sqrt{2}}{2}$¡ÜAF¡Ü3D£®$\frac{2-\sqrt{2}}{2}$¡ÜAF¡Ü$\frac{2+\sqrt{2}}{2}$

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

10£®Èçͼ£¬ÒÑÖªAB¡ÎCD£¬AE¡ÎCF£¬DE=BF£¬ÊÔ˵Ã÷£º
£¨1£©AE=CF£»
£¨2£©AD¡ÎBC£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

16£®ÒÑÖª£¬Èçͼ£¬ËıßÐÎABCDÖУ¬AB=AD£¬¡ÏBAD=¡ÏBCD=90¡ã£¬EΪBC±ßÉÏÒ»µã£¬×÷¡ÏAEF=¡ÏACF=90¡ã
£¨1£©ÊÔÅжÏAEºÍEFµÄÊýÁ¿¹ØÏµ£¬²¢ËµÃ÷ÀíÓÉ£»
£¨2£©µ±ËıßÐÎABCDµÄÃæ»ýΪ16£¬BCµÄ³¤Îª6£¬ÇóADµÄ³¤£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

13£®ÏÂÁÐ˵·¨ÖУ¬´íÎóµÄÊÇ£¨¡¡¡¡£©
A£®ÓÐÀíÊýÖУ¬Ã»ÓÐ×î´óºÍ×îСµÄÊý
B£®ÁãÊÇ×îСµÄÓÐÀíÊý
C£®¦ÐËÄÉáÎåÈ뾫ȷµ½0.1Ô¼µÈÓÚ3.1
D£®¡°Ð¡ÍõÉí¸ß1.60Ãס±Öеġ°1.60¡±ÊǽüËÆÊý

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

14£®ÒÑÖª3x2-4x+6=9£¬Ôò´úÊýʽ6x2-8x+6µÄֵΪ£¨¡¡¡¡£©
A£®9B£®7C£®18D£®12

²é¿´´ð°¸ºÍ½âÎö>>

ͬ²½Á·Ï°²á´ð°¸