ÒÑÖªº¯Êýf£¨x£©=lnx£¬g£¨x£©=£¨m+1£©x2-x£¨m¡Ù-1£©£®
£¨I£©Èôº¯Êýy=f£¨x£©Óëy=g£¨x£©µÄͼÏóÔÚ¹«¹²µãP´¦ÓÐÏàͬµÄÇÐÏߣ¬ÇóʵÊýmµÄÖµºÍPµÄ×ø±ê£»
£¨II£©Èôº¯Êýy=f£¨x£©Óëy=g£¨x£©µÄͼÏóÓÐÁ½¸ö²»Í¬µÄ½»µãM¡¢N£¬ÇóʵÊýmµÄÈ¡Öµ·¶Î§£»
£¨III£©ÔÚ£¨II£©µÄÌõ¼þÏ£¬¹ýÏ߶ÎMNµÄÖеã×÷xÖáµÄ´¹Ïß·Ö±ðÓëf£¨x£©µÄͼÏóºÍg£¨x£©µÄͼÏó½»ÓÚS¡¢Tµã£¬ÒÔSµãΪÇеã
×÷f£¨x£©µÄÇÐÏßl1£¬ÒÔTΪÇеã×÷g£¨x£©µÄÇÐÏßl2£¬ÊÇ·ñ´æÔÚʵÊým£¬Ê¹µÃl1¡Îl2£¿Èç¹û´æÔÚ£¬Çó³ömµÄÖµ£»Èç¹û²»´æÔÚ£¬Çë˵Ã÷ÀíÓÉ£®
£¨I£©É躯Êýy=f£¨x£©Óëy=g£¨x£©Í¼ÏóµÄ¹«¹²µãΪP£¨x0£¬y0£©£¬
ÔòÓÐlnx0=£¨m+1£©x02-x0¢Ù£¬
ÓÖÔÚµãP´¦Óй²Í¬µÄÇÐÏߣ¬
¡àf¡ä(x0)=g¡ä(x0)?
1
x0
=2(m+1)x0-1?m=
1+x0
2
x20
-1
£¬¢Ú
¢Ú´úÈë¢Ù£¬µÃlnx0=
1
2
-
1
2
x0
£®
Éèh(x)=lnx-
1
2
+
1
2
x?h¡ä(x)=
1
x
+
1
2
£¾0(x£¾0)
£®
ËùÒÔ£¬º¯Êýh£¨x£©×î¶àÖ»ÓÐ1¸öÁãµã£¬
¹Û²ìµÃx0=1ÊÇÁãµã£¬¹Êm=0£®
´Ëʱ£¬µãP£¨1£¬0£©£»
£¨II£©¸ù¾Ý£¨I£©Öª£¬µ±m=0ʱ£¬Á½ÌõÇúÏßÇÐÓÚµãP£¨1£¬0£©£¬
´Ëʱ£¬±ä»¯µÄy=g£¨x£©µÄͼÏóµÄ¶Ô³ÆÖáÊÇx=
1
2
£¬
¶øy=f£¨x£©Êǹ̶¨²»±äµÄ£¬Èç¹û¼ÌÐøÈöԳÆÖáÏòÓÒÒƶ¯£¬
¼´x=
1
2(m+1)
£¾
1
2
£¬½âµÃ-1£¼m£¼0£®Á½ÌõÇúÏßÓÐÁ½¸ö²»Í¬µÄ½»µã£¬
µ±m£¼-1ʱ£¬¿ª¿ÚÏòÏ£¬Ö»ÓÐÒ»¸ö½»µã£¬ÏÔÈ»²»ºÏÌâÒ⣬
ËùÒÔ£¬ÓÐ-1£¼m£¼0£»

£¨III£©¼ÙÉè´æÔÚÕâÑùµÄm£¬²»·ÁÉèM£¨x1£¬y1£©£¬N£¨x2£¬y2£©£¬ÇÒx1£¾x2£¬
ÔòMNÖеãµÄ×ø±êΪ(
x1+x2
2
£¬
y1+y2
2
)
£®
ÒÔSΪÇÐÏßµÄÇÐÏßl1µÄбÂÊks=f¡ä(
x1+x2
2
)=
2
x1+x2
£¬
ÒÔTΪÇеãµÄÇÐÏßl2µÄбÂÊkT=g¡ä(
x1+x2
2
)=(m+1)(x1+x2)-1
£®
Èç¹û´æÔÚm£¬Ê¹µÃks=kT£¬
¼´
2
x1+x2
=(m+1)(x1+x2)-1
£®¢Û
¶øÇÒÓÐlnx1=£¨m+1£©x12-x1ºÍlnx2=£¨m+1£©x22-x2£®
Èç¹û½«¢ÛµÄÁ½±ßͬ³ËÒÔx1-x2£¬µÃ
¢Ü
2(x1-x2)
x1+x2
=(m+1)(
x21
-
x22
)-(x1-x2)
£¬
¼´
2(x1-x2)
x1+x2
=[(m+1)
x21
-x1]-[(m+1)
x22
-x2]=lnx1-lnx2=ln
x1
x2
£¬
Ò²¾ÍÊÇln
x1
x2
=
2(
x1
x2
-1)
x1
x2
+1
£®
Éè¦Ì=
x1
x2
£¾1
£¬ÔòÓÐln¦Ì=
2(¦Ì-1)
1+¦Ì
(¦Ì£¾1)
£®
Áîh(¦Ì)=ln¦Ì-
2(¦Ì-1)
1+¦Ì
£¨¦Ì£¾1£©£¬Ôòh¡ä(¦Ì)=
1
¦Ì
-
4
(1+¦Ì)2
=
(¦Ì-1)2
¦Ì(1+¦Ì)2
£®
¡ß¦Ì£¾1£¬¡àh'£¨¦Ì£©£¾0£®
Òò´Ë£¬h£¨¦Ì£©ÔÚ[1£¬+¡Þ]Éϵ¥µ÷µÝÔö£¬¹Êh£¨¦Ì£©£¾h£¨1£©=0£®
¡àln¦Ì£¾
2(¦Ì-1)
1+¦Ì
(¦Ì£¾1)
¢Ý
¡à¢ÜÓë¢Ýì¶Ü£®
ËùÒÔ£¬²»´æÔÚʵÊýmʹµÃl1¡Îl2£®
Á·Ï°²áϵÁдð°¸
Ïà¹ØÏ°Ìâ

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

ÒÑÖªº¯Êýf£¨x£©=2x-2+ae-x£¨a¡ÊR£©
£¨1£©ÈôÇúÏßy=f£¨x£©Ôڵ㣨1£¬f£¨1£©£©´¦µÄÇÐÏßƽÐÐÓÚxÖᣬÇóaµÄÖµ£»
£¨2£©µ±a=1ʱ£¬ÈôÖ±Ïßl£ºy=kx-2ÓëÇúÏßy=f£¨x£©ÔÚ£¨-¡Þ£¬0£©ÉÏÓй«¹²µã£¬ÇókµÄÈ¡Öµ·¶Î§£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

ÒÑÖªº¯Êýf£¨x£©=x2+2|lnx-1|£®
£¨1£©Çóº¯Êýy=f£¨x£©µÄ×îСֵ£»
£¨2£©Ö¤Ã÷£º¶ÔÈÎÒâx¡Ê[1£¬+¡Þ£©£¬lnx¡Ý
2(x-1)
x+1
ºã³ÉÁ¢£»
£¨3£©¶ÔÓÚº¯Êýf£¨x£©Í¼ÏóÉϵIJ»Í¬Á½µãA£¨x1£¬y1£©£¬B£¨x2£¬y2£©£¨x1£¼x2£©£¬Èç¹ûÔÚº¯Êýf£¨x£©Í¼ÏóÉÏ´æÔÚµãM£¨x0£¬y0£©£¨ÆäÖÐx0¡Ê£¨x1£¬x2£©£©Ê¹µÃµãM´¦µÄÇÐÏßl¡ÎAB£¬Ôò³ÆÖ±ÏßAB´æÔÚ¡°°éÂÂÇÐÏß¡±£®ÌرðµØ£¬µ±x0=
x1+x2
2
ʱ£¬ÓÖ³ÆÖ±ÏßAB´æÔÚ¡°ÖÐÖµ°éÂÂÇÐÏß¡±£®ÊÔÎÊ£ºµ±x¡Ýeʱ£¬¶ÔÓÚº¯Êýf£¨x£©Í¼ÏóÉϲ»Í¬Á½µãA¡¢B£¬Ö±ÏßABÊÇ·ñ´æÔÚ¡°ÖÐÖµ°éÂÂÇÐÏß¡±£¿Ö¤Ã÷ÄãµÄ½áÂÛ£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

ÒÑÖªº¯Êýf£¨x£©=x2-bxµÄͼÏóÔÚµãA£¨1£¬f£¨1£©£©´¦µÄÇÐÏßlÓëÖ±Ïßx+3y-1=0´¹Ö±£¬ÈôÊýÁÐ{
1
f(n)
}µÄÇ°nÏîºÍΪSn£¬ÔòS2012µÄֵΪ£¨¡¡¡¡£©

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

ÒÑÖªº¯Êýf£¨x£©=xlnx
£¨¢ñ£©Çóº¯Êýf£¨x£©µÄ¼«Öµµã£»
£¨¢ò£©ÈôÖ±Ïßl¹ýµã£¨0£¬-1£©£¬²¢ÇÒÓëÇúÏßy=f£¨x£©ÏàÇУ¬ÇóÖ±ÏßlµÄ·½³Ì£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

ÒÑÖªº¯Êýf£¨x£©=
3
x
a
+
3
(a-1)
x
£¬a¡Ù0ÇÒa¡Ù1£®
£¨1£©ÊÔ¾ÍʵÊýaµÄ²»Í¬È¡Öµ£¬Ð´³ö¸Ãº¯ÊýµÄµ¥µ÷ÔöÇø¼ä£»
£¨2£©ÒÑÖªµ±x£¾0ʱ£¬º¯ÊýÔÚ£¨0£¬
6
£©Éϵ¥µ÷µÝ¼õ£¬ÔÚ£¨
6
£¬+¡Þ£©Éϵ¥µ÷µÝÔö£¬ÇóaµÄÖµ²¢Ð´³öº¯ÊýµÄ½âÎöʽ£»
£¨3£©¼Ç£¨2£©Öеĺ¯ÊýͼÏóΪÇúÏßC£¬ÊÔÎÊÊÇ·ñ´æÔÚ¾­¹ýÔ­µãµÄÖ±Ïßl£¬Ê¹µÃlΪÇúÏßCµÄ¶Ô³ÆÖ᣿Èô´æÔÚ£¬Çó³öÖ±ÏßlµÄ·½³Ì£»Èô²»´æÔÚ£¬Çë˵Ã÷ÀíÓÉ£®

²é¿´´ð°¸ºÍ½âÎö>>

ͬ²½Á·Ï°²á´ð°¸