¼×¡¢ÒÒÁ½Î»Ñ§Éú²Î¼ÓÊýѧ¾ºÈüÅàѵ£®ÏÖ·Ö±ð´ÓËûÃÇÔÚÅàѵÆÚ¼ä²Î¼ÓµÄÈô¸É´ÎÔ¤Èü³É¼¨ÖÐËæ»ú³éÈ¡8´Î£®¼Ç¼ÈçÏ£¬¼×£º82 81 79 78 95 88 93 84¡¡ÒÒ£º92 95 80 75 83 80 90 85£®
£¨1£©»­³ö¼×¡¢ÒÒÁ½Î»Ñ§Éú³É¼¨µÄ¾¥Ò¶Í¼£¬Ö¸³öѧÉúÒҳɼ¨µÄÖÐλÊý£»
£¨2£©ÏÖÒª´ÓÖÐÑ¡ÅÉÒ»È˲μÓÊýѧ¾ºÈü£¬´Óƽ¾ù×´¿öºÍ·½²îµÄ½Ç¶È¿¼ÂÇ£¬ÄãÈÏΪÅÉÄÄλѧÉú²Î¼ÓºÏÊÊ£¿Çë˵Ã÷ÀíÓÉ£»
£¨3£©¾ºÈü³É¼¨²»µÍÓÚ85·Ö£¬Ôò¸Ã´Î³É¼¨ÎªÓÅÐ㣬Èô½«ÆµÂÊÊÓΪ¸ÅÂÊ£¬¶ÔѧÉú¼×ÔÚ½ñºóµÄÈý´ÎÊýѧ¾ºÈü³É¼¨½øÐÐÔ¤²â£¬¼ÇÕâÈý´Î³É¼¨ÖÐÓÅÐãµÄ´ÎÊýΪX£¬ÇóXµÄ·Ö²¼Áм°ÊýѧÆÚÍûE£¨X£©£®
¿¼µã£º¾¥Ò¶Í¼
רÌ⣺¸ÅÂÊÓëͳ¼Æ
·ÖÎö£º£¨1£©»­³ö¾¥Ò¶Í¼£¬Çó³öÖÐλÊý£»£¨2£©·Ö±ðÇó³ö¼×£¬ÒÒµÄƽ¾ùÊý£¬·½²î£¬´Ó¶øµÃµ½´ð°¸£»£¨3£©ÏÈÇó³ö¹ØÓÚXµÄ·Ö²¼ÁУ¬´Ó¶øÇó³öÊýѧÆÚÍû£®
½â´ð£º ½â£º£¨1£©¾¥Ò¶Í¼ÈçÓÒ£¬Ñ§ÉúÒҳɼ¨µÄÖÐλÊýΪ84£¬
£¨2£©ÅɼײμӱȽϺÏÊÊ£¬ÀíÓÉÈçÏ£º
.
x
¼×
=
1
8
£¨70¡Á2+80¡Á4+90¡Á2+9+8+8+4+2+1+5+3£©=85£¬
.
x
ÒÒ
=
1
8
£¨70¡Á1+80¡Á4+90¡Á3+5+3+5+2+5£©=85£¬
s
2
¼×
=
1
8
[£¨78-85£©2+£¨79-85£©2+£¨81-85£©2+£¨82-85£©2+£¨84-85£©2+£¨88-85£©2+£¨93-85£©2+£¨95-85£©2]=35.5£¬
s
2
ÒÒ
=
1
8
[£¨75-85£©2+£¨80-85£©2+£¨80-85£©2+£¨83-85£©2+£¨85-85£©2+£¨90-85£©2+£¨92-85£©2+£¨95-85£©2]=41£®
¡ß
.
x
¼×
=
.
x
ÒÒ
£¬
s
2
¼×
£¼
s
2
ÒÒ
£¬
¡à¼×µÄ³É¼¨±È½ÏÎȶ¨£¬ÅɼײμӱȽϺÏÊÊ£®
£¨3£©¼Ç¡°¼×ͬѧÔÚÒ»´ÎÊýѧ¾ºÈüÖгɼ¨¸ßÓÚ85·Ö¡±ÎªÊ¼þA£¬
ÔòP£¨A£©=
3
8
£¬Ëæ»ú±äÁ¿XµÄ¿ÉÄÜȡֵΪ0£¬1£¬2£¬3£¬
ÇÒX·þ´ÓB£¨3£¬
3
8
£©£¬
¡àP£¨X=k£©=
C
k
3
£¨
3
8
£©k£¨1-
3
8
£©3-k£¨k=0£¬1£¬2£¬3£©£¬
XµÄ·Ö²¼ÁÐΪ£º
X0123
P
125
512
225
512
135
512
27
512
¡àE£¨X£©=0¡Á
125
512
+1¡Á
225
512
+2¡Á
135
512
+3¡Á
27
512
=
9
8
£¨»òE£¨X£©=np=
9
8
£©£®
µãÆÀ£º±¾Ì⿼²éÁ˾¥Ò¶Í¼ÎÊÌ⣬¿¼²éÁËƽ¾ùÊý£¬·½²îÒÔ¼°·Ö²¼ÁÐÆÚÍû£¬ÊÇÒ»µÀ×ÛºÏÌ⣮
Á·Ï°²áϵÁдð°¸
Ïà¹ØÏ°Ìâ

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

Éè
a
£¬
b
Ϊ·ÇÁãÏòÁ¿£¬|
b
|=2|
a
|£¬Á½×éÏòÁ¿
x1
£¬
x2
£¬
x3
£¬
x4
ºÍ
y1
£¬
y2
£¬
y3
£¬
y4
¾ùÓÉ2¸ö
a
ºÍ2¸ö
b
ÅÅÁжø³É£¬Èô
x1
y1
+
x2
y2
+
x3
y3
+
x4
y4
ËùÓпÉÄÜÈ¡ÖµÖеÄ×îСֵΪ4|
a
|2£¬Ôò
a
Óë
b
µÄ¼Ð½ÇΪ
 
£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

ÒÑ֪˫ÇúÏߵĽ¥½üÏß·½³ÌÊÇy=¡À
1
2
x£¬½¹µãÔÚxÖáÉÏ£¬½¹¾àΪ20£¬ÔòËüµÄ·½³ÌΪ£¨¡¡¡¡£©
A¡¢
y2
20
-
x2
80
=1
B¡¢
x2
20
-
y2
80
=1
C¡¢
y2
80
-
x2
20
=1
D¡¢
x2
80
-
y2
20
=1

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

£¨1£©Ëµ³öÏÂÁÐα´úÂë±íʾµÄË㷨ĿµÄ£®

£¨2£©¸ù¾Ýα´úÂ룬д³öÖ´Ðнá¹û£®
Ëã·¨¿ªÊ¼

Êä³öxµÄÖµ£»
Ëã·¨½áÊø£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

Éèf£¨x£©=lg£¨
2
1-x
+a
£©ÊÇÆ溯Êý
£¨1£©ÇóaµÄÖµ£»
£¨2£©Ö¤Ã÷f£¨x£©ÔÚ¶¨ÒåÓòÉÏÊǵ¥µ÷º¯Êý£»
£¨3£©Èôf£¨t2-1£©+f£¨2t-1£©£¾0£¬ÇóʵÊýtµÄÈ¡Öµ·¶Î§£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

ÒÑÖªº¯Êýf£¨x£©=-x2+mx+1ÔÚÇø¼ä[1£¬+¡Þ£©ÉÏʱ¼õº¯Êý£¬ÇómµÄÈ¡Öµ·¶Î§£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

ÒÑÖªÔ²C£ºx2+£¨y-1£©2=5£¬Ö±Ïßl£ºmx-y+1-m=0£¨m¡ÊR£©£®
£¨1£©ÊÔÅжÏÖ±ÏßlÓëÔ²CµÄλÖùØϵ£»
£¨2£©ÉèÖ±ÏßlÓëÔ²C½»ÓÚA£¬BÁ½µã£¬ÈôÖ±ÏßlµÄÇãб½ÇΪ120¡ã£¬ÇóÏÒABµÄ³¤£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

¹Å´ú¡°ÎåÐС±Ñ§ÈÏΪ£º¡°ÎïÖÊ·Ö½ð¡¢Ä¾¡¢ÍÁ¡¢Ë®¡¢»ðÎåÖÖÊôÐÔ£¬½ð¿Ëľ£¬Ä¾¿ËÍÁ£¬ÍÁ¿ËË®£¬Ë®¿Ë»ð£¬»ð¿Ë½ð£®¡±½«ÎåÖÖ²»Í¬ÊôÐÔµÄÎïÖÊÈÎÒâÅųÉÒ»ÁУ¬µ«ÅÅÁÐÖÐÊôÐÔÏà¿ËµÄÁ½ÖÖÎïÖʲ»ÏàÁÚ£¬ÔòÕâÑùµÄÅÅÁз½·¨ÓжàÉÙÖÖ£¨½á¹ûÓÃÊý×Ö±íʾ£©£®£¨¡¡¡¡£©
A¡¢5B¡¢10C¡¢20D¡¢120

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

Éèf£¨x£©=
4x
4x+a
£¬ÇÒf£¨x£©µÄͼÏó¹ýµã(0£¬
1
2
)
£®
£¨1£©Çóf£¨x£©µÄ½âÎöʽ£»
£¨2£©¼ÆËãf£¨x£©+f£¨-x£©µÄÖµ£®

²é¿´´ð°¸ºÍ½âÎö>>

ͬ²½Á·Ï°²á´ð°¸