内容正文:
(3)ÂKA¦§zT(-1,1)MÃ.
(4)狔=-
3
狓
ßm121-î3@ 狔=-
3
狓+1
,
4ß
k121-î3,@ 狔=1-
3
狓+1
,
f狔=
狓-2
狓+1
.
7.狔=
(狓+犪)(狓+犫)
狓
=
狓2+(犪+犫)狓+犪犫
狓
=狓+
犪犫
狓
+犪+
犫≥2槡犪犫+犪+犫=(槡犪+槡犫)2,!O¸!狓=
犪犫
狓
,
f狓
=槡犪犫"B��,U],ÂK狔=
(狓+犪)(狓+犫)
狓
AÇÈ
C6
(槡犪+槡犫)2.
8.`81jòó6犵(狓),#犵(狓)=
-狓+12狓-25
狓
=12- 狓+
25( )狓 ,
76狓+
25
狓
≥2 狓·
25
槡 狓 =10,U],!狓=
25
狓
"
,
f
狓=5",犵(狓)max=2.
9.狔=
狓
狓2+狓+1
=
1
狓+
1
狓
+1
≤
1
2 狓·
1
狓
+槡 1
=
1
3
.U
]
,
!狓=
1
狓
"
,
f狓=1",狔max=
1
3
.
&17' U+@AHhi
1.槡2 `狓= 槡槡 槡槡3+ 5- 3- 5,#狓2=2,U]狓=槡2.
2.
21
2
76犿,狀F45狓2+5狓+2=0A�>,2犿+狀
=-5,犿狀=2.
U]
犿
狀
+
狀
犿
=
犿2+狀2
犿狀
=
(犿+狀)2-2犿狀
犿狀
=
21
2
.
3.
31
16
`狓-1=狔+3=
狕-1
2
=狋,#狓2+狔2+狔狕=(狋+1)2
+(狋-3)2+(狋-3)(2狋+1)=4狋2-9狋+7=4狋-( )98
2
+
31
16
.2!狋=
9
8
"
,狓2+狔2+狔狕AÇÈCF
31
16
.
4.9&'@狓≥0,狔≥0,狕≥0,O+
3狔+2狕=3-狓,
3狔+狕=4-3狓
{
.
2
狕=2狓-1≥0,
狔=
5
3
(1-狓)≥0
烅
烄
烆
.
73
1
2
≤狓≤1,TF狋=
1
3
(43狓-
22).U ] ! 狓=
1
2
"
,狋 B Ç È C 6
1
3
×
43×
1
2
-( )22 =-16.!狓=1",狋B ÇÙC6
1
3
×(43-22)=7.
5.r45A>FÂK狔=|狓|7狔=犪狓+1A¦§¬
A9ÊË
,
ÂK狔=|狓|A¦§F®,、w§°A:1
ÀÆ
,
ÂK狔=犪狓+1F¹s�(0,1)AÅÆ.45
|狓|=犪狓+1+Ó>p<I>,¿;Fs(0,1)AÅ
Æi®w§°A:1ÀÆh¬pSi®,§°A:
1ÀÆh¬.u¦X<,-1≤-
1
犪
<0,U]犪≥1.
6.(1)狔=
40狓+犪
40
,
f40狔=40狓+犪.
(2)̀ =>(P"Ý?狀-@Þ,9&'@
犪+40狓=40狔,
犪+15狓=30狔,
犪+8狓≤8狀狔
烅
烄
烆 .
①
②
③
9①,②X@狓=
犪
60
,狔=
犪
24
,
��③@犪+8×
犪
60
≤8狀×
犪
24
,
f狀≥
17
5
=3
2
5
.2狀
=4.
7.76Aòó犛=狆+狇,ABC3#..
`BCD÷ú狓#.,#BCE÷ú(3-狓)#.,犛=
1
5
狓+
3
5
3-槡 狓(0≤狓≤3).
¡狋= 3-槡 狓,#0≤狋≤槡3,TF犛=
1
5
(3+3狋-狋2)=
-
1
5
狋-( )32
2
+
21
20
.
!狋=
3
2
<槡3",犛max=
21
20
.3"狓=3-狋2=0.75(#
.
),3-狓=2.25(#.).
73
,
MD
、
E�F÷úACGB�Àë60.75#.
72.25#.",Lñ@ÇÙAòó61.05#..
8.9狓+狔+狕=5,@狓+狔=5-狕.9狓狔+狔狕+狕狓=
3,X@狓狔=3-(狓+狔)狕=狕2-5狕+3.73,狓,狔XH
6zT狋A,.wx45狋2-(5-狕)狋+狕2-5狕+3=
0A�-=>.U]Δ=(5-狕)2-4(狕2-5狕+3)≥0,
?@-1≤狕≤
13
3
.
9.I狆H6J¨µ,狓H6KK,LMÂK狔=犳(狆)=
(狓-1)狆+(狓2-4狓+3).3ÂKA¦§F,±Æ&.
()狔>0Ñ��,!O¸!犳(0)=狓2-4狓+3>0,]
N犳(4)=4(狓-1)+(狓2-4狓+3)>0.?�-S�l
�fXV@狓ABCDE6狓<-1;狓>3
.
·37·
2 3 4 5
$$
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