内容正文:
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(
*
)
+#,"-.
*
、
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DBDCDB AABDBA
23
:
1.
!"#$%&'
,
()*+
x2-2x-3≥0,
x+2>0{ ,
,-
x≥3. x≤-1,
x>-2{ ,
/01-
,
#$23'45
(-2,-1]∪[3,+∞).
2.
3'45
R
26#$
f(x)
*+ (fx+ )32 =
(f 12 )-x ,78 (fx+ )32 (=f 12 ) (-x =-fx-
)12 ,9 f(x+2)=-f(x),
( (f )52 (=f2+ )12 (=-f )12 (=- )12
3
=-1
8
,
:;
(B).
3.
<#$26=>1?
(A),(C)
@56#$
,
A
B
;
C?
(B)
D#$E
(-∞,0)0FGHI,AB;<
#$JK1?
(D)
D#$E
(-∞,0)0FGHL,:
;
(D).
4.
M
log2x=log3y=2
z
=p,
78
p>0,
M
y1 =
log2x,y2 =log3y,y3 =2
z
,
N
O
3
P#$2JK
,
QJ
1
7
R
.
<J1?
:z<x<y.
5.
S
f(x)=y=x
2
8
-ln|x|,
(
f(-x)=f(x),
:
f(x)
5=#$
,
AB;T
(B);
U
x>0
V
x→0W,
y→+∞,AB;T(A);U x= 槡22W,y=1- 槡ln22
<1-lne=0,
AB;T
(C).
:;
(D).
6.
X5#$
f(x)
5=#$
,
7 8
f(a) (= flog2 )13 = f(-log2 3) =
f(log23),f(b) (=flog4 )15 =f(-log45)=f(log45),
X5=#$
f(x)
E
(-∞,0]0FGHI,
78
f(x)
E
(0,+∞)0FGHL,
Y
1=log44<log45=
1
2
log25=log2槡5<log23
<log24=2<2
3
2,
78
f(b)<f(a)<f(c).
7.
<Z&?
,f(x)
23'45
R,
YX5
f(-x)=
log2020( x
2+槡 1-x)=log2020
1
x+ x2+槡 1
=-f(x),
:
f(x)
56#$
,
YX5
f(x)
E
(0,+∞)0FGHL,78f(x)=
log2020( x
2+槡 1+x)E x∈R0FGHL,
([\
x
2]^_
f(1-2x)+f(1)>0
1`a5
f(1-2x)>-f(1)=f(-1),
78
1-2x>-1,
,-
x<1.
:;
(A).
8.
S
g(x)=x3-ax,
<
g(x)>0,
1-
x∈( 槡- a,
0)∪(槡a,+∞).<g′(x)=3x
2-a,
S
g′(x)=0,
-
x
=± a槡3.U x (∈ 槡- a,-
a
槡 )3 ,(槡a,+∞)W,
g′(x)>0;
U
x (∈ - a槡3, )0 W,g′(x)<0.:g(x)
(E 槡- a,- a槡 )3 ,(槡a,+∞)0FGHL,
(
E
- a槡3, )0 0FGHI.
U
a>1
W
,
< b c # $ F G > 1 -
,f(x)
(
E
- a槡3, )0 0FGHI, (E 槡- a,-
a
槡 )3 ,(槡a,
+∞)0FGHL,]cZ&;
U
0<a<1
W
,
<bc#$FG>1-
,f(x)
(
E
- a槡3, )0 0FGHL, (E 槡- a,-
a
槡 )3 ,(槡a,
+∞)0FGHI.d#$f(x) (Eef -12, )0 0F
GHL
, (: -12, )0 ( - a槡3, )0 ,
78-
- a槡3≤-
1
2
,
:
a≥
3
4
,
78g$
a [2hijk5 34, )1 .:;(A).
9.
lm&2
x1∈[1,3],nE x2∈[1,3],
"-
f(x1)f(x2)=g(x1)g(x2)op,
95
g(x1)
f(x1)
=
f(x2)
g(x2)
,
9
ax1-1=
1
ax2-1
op
,
qrU
0<a≤1W,y=
g(x)
f(x)
=ax-1
E
[1,3]
2i45
[a-1,3a-1],
d
a-1∈(-1,0],9y=ax
-1
2#$iDOs
0,
]op
,
tu
;
U
a>1,
1-
ax1-1E[1,3]2i45[a-1,3a
-1], 1
ax2-1
E
[1,3] [2i45 13a-1, 1a- ]1 ,
<Z&1-E
[1,3]
v
,ax1 -12i45
1
ax2-1
2i42wx
,
1-
1
3a-1≤
a-1<3a-1≤
1
a-1
,
1-
(a-1)(3a-1)=1,
,-
a=4