17. -------------------------------------------------------------------------------- – -----------------------------------------------------------------------------
116 (2020) .4/15
202 1 2 201, ,..., .
, 1,2,...,202,i i 99,i 201.i
:
: 202,203,...,300 100.101,...,201i i , .
200 . 200
. , 200 i
200,...,i , 1,2,...,100.i : 200 201 , 1,2,...,100.i ii i i
60. 2
f x x bx c, ,b,c ,
:
2 21 3
x 2x 2016 f x x 6x 2020
2 2
.
2014
:
2 221 3
2 2014 2 2014
2 2
x f x ax bx c x (1)
(1) :
2014 2 2014 2 2014f f
4 2 2014a b c (2)
, (1) 1 3x x :
1 1
2014 2015 2015
2 2
a b c a b c (3)
1 1
2014 9 3 2015 2015
2 2
a b c a b c . (4)
(2) – (4) : 1, 4, 2018,a b c
22
4 2018 2 2014.f x x x x
2
2 2014f x x (1)
.x
49. , .
1 2
. 1 2
. . 2
. , .
2014
, ,
.
, , , , 3 ,
0ˆ ˆ 90 . 1 2, 1 3,
, ( 2 3, ,
, , .
29. 116 (2020) .4/27
: …
.
.
1
A1) 2
, 0,x x
1 2, ,x x :
1 2x x 1 2 .x x 13
2)
,
, ,
.
a) , :
0 0 0 .
b) , , .
c) 0, : .x x x
d) 0, , .
e) 2
, 0x x
1 2, ,x x :
2
1 2 .x x x x x x
f) ,
, , , .
12
1) , 1 3.x
8
B2) , 2
5 0.x x
8
B3)
2
1
1 3 .
5
f x x
x x
9
.
, , :
3 6
2 2 2.
1) : 2. 8
2) :
3 3
.
2 4 2
x x
8
3) :
11 6 5 2
0.x x x 9
2
5 6
.
2
x x
f x
x
1) A
.f 6
2) : 3, .f x x x A
6
3)
.f 6
4) :
2
2 4, .f x x x A 7
2
1) : ,
, . ; 13
2)
,
, ,
.
a) 2
, .
b) 0,
, .
c)
, ,f x x
.
d) ,
x .x
e) 2
, 0,x x
37. 116 (2020) .4/35
:
-
: alog x
x=
x
x log .
:
log x
log x
log
, ’
:
i) 10
: 10log x : log x
ii) e
: elog x : ln x
1.
i) 3 3 32log 12 log 80 log 45
ii) 3log2 2log30 log72
iii) 2 3 4 99log2 log 3 log 4 log 5 log 100
i) 3 3 32log 12 log 80 log 45
4
3 3 3
144 45
log log 81 log 3 4
80
ii) 3 2
log2 log30 log72
3 2
22 30
log log100 log10 2
72
iii)
log3 log4 log5 log100
log2
log2 log3 log4 log99
log100 2 .
iv)
2. : x x
ln(1 e ) ln(1 e ) x
x
x x
x
1 e
ln(1 e ) ln(1 e ) ln
1 e
x x
x
x
x x
1 e 1 e
ln ln lne x
1 e 11
e e
3. :
i) x
x log(1 5 ) (x 1)log2
ii) lnx x
x = lne
iii) 4 4 2 2log (log x) log (log x) 1
i) x ,
:
x x x 1
log[10 (1 5 )] log2
x x x 1
10 (1 5 ) 2 x x x x
2 5 (1 5 ) 2 2
x x
5 (1 5 ) 2 . x
5 0 ,
2
1 2 2 0 1
2 , 1
x
5 1 x 0
ii) x 0
: ln x
x = x .
,
,
lnx
lnx =lnx lnx lnx=lnx lnx(lnx 1) 0
ln x 0 ln x 1 x 1 x e ,
.
iii) 4log x 0 x 1
,
: 2 4
2 2
2
log (log x)
log (log x) 1
log 4
2 4
2 2
log (log x)
log (log x) 1
2
2 4 2 2log (log x) 2log (log x) 2
2 2
2 4 2 2 2log (log x) log (log x) log 2
2
2
2 4 2
(log x)
log (log x) log
4
2
2
4
(log x)
log x
4
2
2 2log x (log x)
2 4
2
2 22log x (log x) . 2log x
2
2 0 2 ,
2log x 0 x 1 ,
2log x 2 x 4, .
4. f :
f(x) ln(1 x) ln(1 x)
i)
ii) f
iii) f
iv) f
v) f(x) ln(4x 1)
i) f 1 x 0 1 x 0
x 1 x 1 1 x 1
A 1,1
ii) 1 2x ,x
1 21 x x 1 1 21 x x 1
1 22 1 x 1 x 0
38. _______________________________ B ______________________________
116 (2020) .4/36
1 2ln(1 x ) ln(1 x ) (1)
1 21 x x 1 1 20 1 x 1 x 2
1 2ln(1 x ) ln(1 x ) 1 2ln(1 x ) ln(1 x ) (2)
(1), (2) :
1 1 2 2ln(1 x ) ln(1 x ) ln(1 x ) ln(1 x )
1 2f(x ) f(x ), f
iii) x x
f ( x) ln(1 x) ln(1 x)
= [ln(1 x) ln(1 x)] f (x) , f .
iv) f (x) 0 ln(1 x) ln(1 x) 0
ln(1 x) ln(1 x) 1 x 1 x x 0
f (0) 0 f ,
x 0 f (x) f (0) f (x) 0
x 0 f (x) f (0) f (x) 0
v) x ,
4x 1 0
1
x ( ,1)
4
.
: ln(1 x) ln(1 x) ln(4x 1)
ln(1 x) ln(1 x) ln(4x 1)
1 x (1 x)(4x 1)
2
1 x 4x 1 4x x 2
4x 4x 2 0
2
2x 2x 1 0 , 2 0 , 4 8 12 ,
1,2
2 12 2 2 3 1 3
x
4 4 2
,
1
1 3
x
2
2
1 3
x
2
1 2x ,x
1 3 1 3 1
x (( , ) ( , )) ( ,1)
2 2 4
1 3
x ,1
2
(
1 3 1
2 4
2 2 3 1 2 3 3 12 9 )
5. f :
2 2
f(x) ln x lnx ln(x 1) ln2
i)
x 1
f(x) ln
2 x
x
ii) f
iii) f(x) ln(3x)
i)
2 2
x 0 x 0 x 1 0
x 0 x 1, 1,0 0,
f (x) ln x 2ln x ln(x 1) ln 2
ln x ln(x 1) ln 2
ln(x 1) ln 2 ln x
x 1
ln
2 x
, x
ii)
x 1
f (x) 0 1
2 x
x 1 2 x , x 0
x 1 2x x 1 , x ( 1,0)
x 1 2x 3x 1
1
x
3
, .
iii)
x 1
f (x) ln(3x) ln ln3x
2 x
x 1
3x x 1 6x x
2 x
, x 0
2 2
x 1 6x 6x x 1 0, 25 0 ,
1 2
1 5
x ,x
12
, 1
1
x
2
2
1
x
3
, x ( 1,0) 2
x 1 6x
2
6x x 1 0 , 23 0 , .
6.
4 3 2 2
P(x)=x 3x ln 4x ln
x 1
, 0 x 1
P(1)=0 2
1 3 ln 4ln =0
2
1 3 ln 4ln =0 , ln
4 0
2
3 4 1 0 1 2
1
3
,
ln 1 e 31
ln e
3
7. :
23 log x ln(x 1)
2 e log1,25 log8
x 0 ,
2
3
log x
2
(x 1) log(1,25 8)
2
28
x 1 log10 8 x x x
x
36
2
1,2
2 6
x 2x 8 0 x
2
x 4( .)
x 2( )
8. f : x
f(x) ln(2 e )
i)
- 1
4
39. _______________________________ B ______________________________
116 (2020) .4/37
ii) f
iii) : f(2x) ln7 f(x)
iv) f(ln2) f(1)
i) x x
x ln 22 e 0 e 2 .
( ,ln 2)
ii) 1 2x ,x
1 2x x
1 2x x ln 2 e e 2
1 2x x
e e 2 1 2x x
2 e 2 e 0
1 2x x
ln(2 e ) ln(2 e ) 1 2f (x ) f (x )
f
iii) f(2x) ln7 f(x) 2x x
ln(2 e ) ln7 ln(2 e )
x
e
2x x 2x x
2 e 7(2 e ) e 7e 12 0
2
7 12 0 3 4.
x
e 3 x ln3 x
e 4 x 2ln 2
iv) 2 e ln2 lne ln2 1
f . f ln2 f 1
9.
x
e 1
f(x)
2e
, .
23
ln8 log 100 ln(log0,001) ln4
i)
2x
3
f(x)
2
ii) N :
1 1
f(2x ) f(x) f( ) 0
2 2
i)
2
3 3 2 23
ln 2 log10 ln(log10 ) ln(2 )
22
3ln 2 ln( 3) 2ln 2
3
2ln2 ln9 2ln2
2ln 2 2ln3 2ln 2 2ln3,
ln9
e e 9
x x
8 4
f(x)
18 9
2x
3
2
ii)
1 1
f (2x ) f (x) f ( ) 0
2 2
.
1
2(2x ) 2x 1
23 3 3
0
2 2 2
4x 1 2x 1
3 3 3
0
2 2 2
4x 2x 1
3 2 3 2
0
2 3 2 3
,
2x
3
0
2
,
2 2 2
0
3 3
25 0
2 1
2 3 2 0 2
2
,
.
2x
3 3
2 2xln ln 2
2 2
ln 2
x
2(ln3 ln 2)
10. :
i) 2x x
ln(ln(e 2e 2)) 0
ii)
lnx 2 lnx 3
1
lnx lnx 1
i) 2x x
e 2e 2 1,
x 0, 2x x
ln ln(e 2e 2) 0
2x x 2x x
ln(e 2e 2) 1 e 2e 2 e
2x x
e 2e 2 e = 0
x
e 0 , :
4 e 1 0
2
2 2 e 0 1 e 1 0
1 e 1 ,
x
e 1 e 1 x ln(1 e 1 ).
ii) : x 0 ln x 1
1
x
e
, ln x 0 x 1,
1 1
x (0, ) ( ,1) (1, )
e e
,
ln x 2 ln x 3
1
ln x ln x 1
(lnx 2)(lnx 1) lnx(lnx 3) lnx(lnx 1)
2 2
2ln x 2ln x 2 ln x ln x
2
ln x ln x 2 0 ln x 1 ln x 2
2
1
x e x
e
11.
2 4 8
1 1 1
, ,
log 3 log 3 log 3
.
, ,
2
4 2 8
2 1 1
log 3 log 3 log 3
,
( )
2 2
4
2
log 3 log 3
log 3
log 4 2
2 2
8
2
log 3 log 3
log 3
log 8 3
2 2 2 2 2
4 1 3 4 4
log 3 log 3 log 3 log 3 log 3
.
44. 116 (2020) .4/42
:
– .
1 . 1
2 2
:C x y 1
2
2 2
:C x 3 y 2 4
) .
)
1 2K K .
) C1 C2
( , ),
, .
) ( , ), (
C1, C2) -
.
: ) 1
2 2
:C x y 1, 1K (0,0) 1R 1
. 2C 2K (3,2) 2R 2 .
2 2
1 2 2 1KK 3 2 13 1 R R ,
.
) 1 2K K , -
1 2K Ky x
1 2K K
2
3
1 2
2
K K : y x
3
.
) 1 2C ,C
, , . M M'
1 2C ,C ,
1 2AB M M
1
1 2
2 2
:
2
K K : y x
3
C x y 1
3 13 2 13
,
13 13
,
3 13 2 13
,
13 13
.
1 2
min
M M AB .
( , )
3 13 2 13
,
13 13
6 13 4 13
3 ,2
13 13
)
2 2
2
1 2
C : x 3 y 2 4
2
K K :y x
3
6 13 4 13 6 13 4 13
3 ,2 , 3 ,2
13 13 13 13
.
1 2
max
M M ( , )
3 13 2 13
,
13 13
6 13 4 13
3 ,2
13 13
.
2 . ,
2t,t 3 , t ,
B 1, 2 3 , 1 .
i.
t R -
: x 2y 6 0 .
ii.
1 .
iii. t AB 2B ;
iv. t 2 -
1 : y x 9
2 : y x 1.
v. , 1 2
.
: i. x 2t y t 3 .
:
x 2t x 2t
x 2y 6 0
y t 3 2y 2t 6
: x 2y 6 0 .
ii. B , -
.
B 1 2 2 6 0 2 3
3 2 1 6 0 2 1
46. --------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------
116 (2020) .4/44
2 2
3 2 2 4 4 27 0
2 2
9 12 4 4 16 16 108 4 0
2
25 100 0 2
25 4 0 2
4
2 2.
) 2 2
A B
K ,
2 2
3 2
K , 2 1
2
2 2 2
A B 4 5 4
2 2
.
) K x,y :
3 2
2x 3 2x
2
y 2 1
y 2 1
4x 6 4 1
3y 6 3 2
(1)
(2) : 4x 3y 7 (3).
2 3 6 3 2 4
3 2
2
2
3 2
2 x 2
2
2 3 6 3 2 8
3 2
4
2
3 2
4 x 4
2
x 2 (3) y 5
x 4 (3) y 3 .
-
: 4x 3y 7 ,
M 2, 5 x 2 -
: 4x 3y 7 ,
N 4,3 x 4 -
M N .
5 . :
2 2 2
x + 2 x 2( 1) + ( 1) = 0 (1)
) R -
(1) .
) -
,
( ): 3x + 4 - 8 = 0 .
: )
2 2 2 2 2
A B 4 4 4( 1) 4( 1) 2
4 0 .
0 -
0, 1 .
0
, 1 .
2 2 2
A B 4 4
R
2 2
.
) (1)
( )
2 2
3 4( 1) 8
d(K,( )) R
3 4
7 12
7 12 5
5
6 1.
6
2 2
6(C ): x 12x 10 25 0 , = 1
2 2
1(C ):x 2x 0
6 .
B 1,1 ,
2x y 5 0
x y 1 0. : i. .
ii. .
iii. -
.
iv. .
v. .
: i. 2 ,
1
2
.
1
:y 1 x 1 x 2y 3 0
2
.
ii.
A A .
2x y 5 0
x,y 2,1
x y 1 0
, A 2,1 .
.
2x y 5 0 7 11
x,y ,
x 2y 3 0 5 5
,
7 11
,
5 5
.
iii. -
.
A
O
x x 17
x
2 10
, A
O
y y 16
y
2 10
,
17 16
O ,
10 10
.
O BE :
B E
O E
x x 22
x x
2 5
B E
O E
y y 11
y y
2 5
,
22 11
E ,
5 5
.
iv.
.
3,0
3 6
,
5 5
,
3 0
1 9
. .3 6
2 5
5 5
18
. .
5
47. --------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------
116 (2020) .4/45
v.
.
: Ax x 4
x x
2 5
Ay y 17
y y
2 5
,
4 17
,
5 5
.
7 .
2
2 2 25
x y 3 4 x 4 3 y 0
4
1 ,
, .
A. 1
.
B.
:
i. ii.
iii. u 3 4 v 4 3
.
:
.
2 2 2
2 2 25
4 3 4 4 3 4
4
2 2 2 2
3 4 4 3 25 25 0 ,
.
3 4 4 3
,
2 2
2
25 5
2 2
.
. i.
:
3 4 3 4 5
...
2 2 2
2 2
16 24 16 0
2 2
2 3 2 0 1
4 3 4 3 5
...
2 2 2
2 2
9 24 9 0
2 2
3 8 3 0 2
1 2 :
2 2
3
2 2 2
2 3 2 0
3 8 3 0
2 2
2 2
6 9 6 0
6 16 6 0
25 0 0 -
.
ii. 1
2 :
2 2
8
2 2 3
2 3 2 0
3 8 3 0
2 2
2 2
16 24 16 0
9 24 9 0
2 2 2 2
25 25 0
iii. :
u v 3 4 4 3 ...
2 2
12 0 , , u v .
8 . ,
2
y 2px ,
. x'x
AB , . -
: (A ) (B )
: 2
C: y 2px .
, A AA(x ,y )
B BB(x ,y ) 2
B By 2px 2
A Ay 2px
A Bx x .
A Bx x
-
1 A A: y y p (x x )
2 B B: y y p (x x )
o o(x ,y ) :
o B o By y p (x x ) o A o Ay y p (x x ) ,
o o: y y p (x x) -
B A
AB
B A B A o
y y 2p p
x x y y y
B A
o
y y
y
2
oy y
AB ,
.
48. 115 (2020) .4/46
: …
1. ;
. , f
R f 0 0 .
. f
R
f x 0 x R .
:
2. «
x 1 ,x 1
f (x)
x 1 ,x 1
».
.
3. f
;
4. «
1
f(x)
x
».
.
5. «
A 1,5 B 3,3 ,
f ».
.
6. 1 2x x
6 3
1 2x x
; .
7. : x ,x 0,
3 2
3
x
2
; .
8. x
e ln x .
;
:
« x 1,2 x
ln x x e ».
;
:
, , B 2
(1,0), (0,1) .
1. : 2
2. :
1
2 2
2
3. :
1
1 2 2
2
4.
1
f( ) 2
2
, g( ) 1 2
,
.
:
1.
x AM , M
.
2.
:
2
2
x ,0 x 1
(x) x 8x 4
,1 x 4
3
« ».
:
x,0 x 1
f (x)
4 12 3x,1 x 4
3. , ,
f x ,E x .
4. I.
f 0,1
.
f 1,4
5. -
, E x y x .
,
49. --------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------
115 (2020) .4/47
,
,
f x .
;
1 ,
2 :
1
2 2
2 2
2
1 1
3 5 106
3 5 152
2
2 2
1
2 1
,
: 2
f( ) ln( 1)
, :
2 4 3
2
1
P(x) ( )x ln(e )x
1
2 2 2 lna
( )x (e 1)x ln1 1
1. f
2. f 0 .
3. f ( ) 0, 0 .
4. 0
5.
6. 3 2
P(x) x x x 1
7. :
.
P( )
1, [0, )
1 2
. 2
P( ) 1 2 x x 1 2
2 2x 1,
x (0, )
2
, .
1.
. f ,
x R f x f x , x 0
f 0 f 0 2f 0 0 f 0 0 .
. f
x R
f (x) f ( x)
f (x) f ( x)
2f (x) 0 f (x) 0
2. . , 1 1, ,
x A x A .
x 1 x 1,
f x x 1 f ( x) ( x) 1 x 1 f (x)
x 1 x 1, f x x 1
f x x 1 x 1 f (x)
x A : f x f(x) , .
3. .
. fA ( ,0) (0, ) ,
f
1A ( ,0) 2A (0, ) .
1 2 1x ,x A 1 2x x
1 2
1 1
x x
,
1f A . 1 2 2x ,x A 1 2x x
2f A . 1 2x 0 x
1 2
1 1
0
x x
1 2f (x ) f (x ) f
! f
( )
, 1A , 2A .
. . f
.
4. . . x ,
6 3
5. . .
1 x 1
1
3
6. x
ln x 1,2
1 x 2
e 1,2
1 x 2 ln1 ln x ln 2
1 x 2 e e e
<
<
x 2
0 lnx ln2 lne 1
2 e e e
2 e ln 2 lne x
lnx 1 x 2 e
x
lnx x e x [1,2],
1.
( ) 2 2
2
( )
1
2
2.
2 2
2
1
2 ,
1
2 2
2
3. 1 :
1 1
1 2 2 2
2 2
:
1
2 1 2
2
2 :
1 1
2 1
2 2
1
2 (1 2 )
2
50. --------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------
115 (2020) .4/48
3 : 2 , ,
, 2 .
1 1 1
1 1 90 2 2
2 2 2
1
2 2
2
. :
1
2 1 2
2
4.
1 2 2
f 2 ,
2 2
.
: f 0,
2
f ,
2
g( ) 1 2 ,
.
g 0,
4
,
3
,
4
3
,
4 4
.
1. 0 x 1
, :
x
2x,
1 2
21
x x 2x x ,0 x 1
2
1
( ) 1 2 1
2
1 x 4:
( )
( )
2
x 1, :
3
2 3
3 x 1 4 x
2
2 3 3
x 1, 2 . :
4 x
2 2 x 1
3
2
4 x 7 x
1 x 1 x 1
3 3
2
3
8x x 7
.
2
x 8x 7
3
:
2
x 8x 7
x 1
3
2
x 8x 4
,1 x 4
3
.
2
2
x ,0 x 1
E x x 8x 4
,1 x 4
3
2. :
1 2x ,x 0,1 2 2
1 2 1 2x x x x 1 2 )x (x
1 2x ,x 1,4 1 2x x
2 2 2 2
1 2 1 2
1 2 1 2
x x x x
8x 8x 8x 4 8x 4
2 2
1 1 2 2x 8x 4 x 8x 4
2 2
1 1 2 2
1 2
x 8x 4 x 8x 4
(x ) (x )
3 3
1x 0,1 2x 1,4 1 2x x :
2
1 1 1x 0,1 :0 x 1 0 x 1 10 (x ) 1
2
2 2 2 2
1 8 4
x 1,4 : x x x
3 3 3
,
1
0
3
( 4, 4)
2 4
2
x 8x 4
x
3
,4 4, .
1,4 E x
2 21 x 4 1 x 4 21 x 4
1 20 (x ) 1 x 4 .
1 2 )x (x .
1 2x ,x 0,4 1 2x x
1 2 )x (x , « ».
51. --------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------
115 (2020) .4/49
3. 0 x 1: 2 4 3
x x x x x x 1 0
x 0 0,1 x 1 (0,1]
, A 1,1 .
2
x 8x
41
4
12 3
3
4 xx :
2
x 8x 4 12 3 12 3x
2
x 4 3 12 3x
4
x 4 27 x 4 0
x 4 4,4
x 1 1,4 .
4. . f 0,1
. f 1,4 .
5.
, ,
, x
.
:
1 E x ,f x
y x .
2 f x
E x y x .
1. 2 2
0 1 1
2 2
1 1 0. R
2. 1 2, 0, 1 2
1 2
0
2 2 2 2
1 2 1 2
1 2 1 2
1 1 2 2
1 2
1 2
1 1
1 2... f f ( ), f 0,
3.
2
f( ) 0 ln( 1) ln1
2
1 1
1 0
2 2
0
1 2 1
0 1
f 0, 0 .
4.
2 2
2 2
1
1
3 5 106
25
:
1 1
3 5 152
3 5
5.
2 2
2 2
25 3 5 25 106
5 3 3 5 15 152
2
2
3
5
:
25 25 106
2
5 3 15 152
, : 0
6.
2 2
2( 0) 2
7. :
2 2
2 2
1 1
0
1 1
ln e ln e 0 lne 1
2 2 2 2
1
lna
e 1 1 1 ln1 1 0 1 1
: 4 3 2
P(x) 0x 1x 1x 1x 1
8. .
1
11
0 1
0,
2
3 2
1 1
0 1
3 2 2
0 1 0
0 1 0 1
2
0 1
0 1
.
0
. 0: P( ) 1 1 1 0 , :
2 2
2 x x 1 2 2x 1
2 2
2 x x 1 2x 1
x 0,
2
2 2 2
4 x x 1 2x 1
0 x 1
0 x 1
2 2 2 2
4 x x 4 x (2 x x) 1
0 x 1 0 x 1
2
4 x 1
x
30 x 1
52. 116 (2020) .4/50
T :
1
2
f : ,
2
0 ,0 0,
2 2
x :
0
2 2
0 0
0
x x
0
x f x x f x
lim x 1
x x
:
1. 2
x f x x 1 ,
,0 0
2 2
x , .
2.
2
x x
, x ,0 0,
f x 2 2x
0 , x 0
.
3. f
4. f
.
5.
x 1 2
f x
lim , 0,1
1 1
f x f x
2 2
.
1. 2
A x x f x ,
x ,
2 2
,
2 2
,
.
0 ,0 0,
2 2
x :
0
2
0
2 2
0 0
0
x x
0
A x x f x
0
0
x x
0
x f x x f x
lim x 1
x x
A x A x
lim x 1
x x
A
,0 0,
2 2
A x x 1
2
x f x x 1, x ,0 0,
2 2
.
2. x ,0 0,
2 2
:
2
x f x x x
2
,
2
A x x
2
f x , x B x x x ,
,
2 2
x
,0 , 0,
2 2
,
1 2c ,c , :
2
1
2
2
x f x x x c ,x ,0
2
x f x x x c ,x 0,
2
x 0 :
2
1 1
2
2 2
0 f 0 0 0 c c 0
0 f 0 0 0 c c 0
2
2
x f x x x,x ,0
2
x f x x x,x 0,
2
2
x f x x x,x ,
2 2
2
x x
f x , x ,0 0,
x 2 2
f 0x 0
:
x 0 x 0 x 0
x 0 x 0 x 0
0
0
2
2D.L.H
0
0
D.L.H
x xx x
f 0 f x
x
x
x 1 xx 1
0
2x 22x
lim lim lim
lim lim lim
2
x x
, x ,0 0,
f x x 2 2
0, x 0
53. _______________________________ ______________________________
116 (2020) .4/51
3.
x ,0 0,
2 2
:
2
4
2 2 2
4
4
3
x 1 x x x 2x
f x
x
x x x 2x x 2x
x
x x x x 2 x 2x
x
x x x 2 x
x
0x 0 :
x 0 x 0 x 0
x 0 x 0 x 0
x 0 x 0
2
3
0 0
0 0
2
3 2D.L.H D.L.H
x x
0f x f 0 x xx
x 0 x x
x x x 1x 1
3xx 3x
x 1 x 1 1
1 .
6x 6 x 6 6
lim lim lim
lim lim lim
lim lim
3
x x x 2 x
, x ,0 0,
2 2x
f x
1
, x 0
6
4.
x ,0 0,
2 2
:
3 3
g xx x x 2 x
f x
x x
g : , ,
2 2
g x x x x 2 x
g 0 0
x ,
2 2
,
g x x x x 1 2 x
x x x 1.
g 0 0
g x x x x x x x
g 0 0, g 0
2
g 0
2
.
x ,0
2
, x 0 x 0
x 0 , x x 0 g (x) 0
x 0,
2
, x 0 x 0
x 0 , x x 0 g x 0
g
g
x
2
0
2
g x
g . . 1 . . 2 . .
1
2
1
2
g 0 0
g x
,0 0,
2 2
g
,
2 2
,
g :
,0
2
0, ,
2
g
0x 0 , g 0 0.
x ,
2 2
:
g x g 0 0
x 0 .
54. _______________________________ ______________________________
116 (2020) .4/52
x ,0 0,
2 2
g x 0 g
0x 0 , g
,
2 2
.
x ,0
2
:
g ,
2 2
x 0
2
3
x 0
3
g x
g x g 0 0 0 f x 0
x
x 0,
2
:
g ,
2 2
x 0
2
3
x 0
3
g x
g x g 0 0 0 f x 0
x
x ,0 0,
2 2
f x 0 f
0x 0, f
,
2 2
. f
,
2 2
x ,
2 2
f f x f
2 2
,
f 2x
2
2 2 2 2
2
1 4 22 2 2 2f
2
4 42
1x
2
2 2 2 2
2
1 2 42 2 2 2f
2
4 42
5.
x 1
x f :
x 1
lim x
limf x lim f f 0
0,1
f ,
2 2
0 f f 0 f 0
2
.
, :
f :
2
x 1
1 1 1 1
lim f x f x f 1 f 1 0
2 2 2 2
, 0.
0
21 1
f x f x
2 2
0x 1, x 1.
:
x 1 0
2 2 1 1
x 1 x x x x
2 2
2
f ,
2 2
2
1 1
x , x ,
2 2 2 2
1 1
f x f x
2 2
2
21 1
f x f x 0
2 2
, 2
x 1
1 1
lim f x f x 0
2 2
,
1
0
x 1 2
1
lim
1 1
f x f x
2 2
,
x 1
2
f x
lim
1 1
f x f x
2 2
f
f 0x 1
2
1
lim f x
1 1
f x f x
2 2
2
f : ,
f 0 0 .
f .
1. x
2 3x 1 .
55. _______________________________ ______________________________
116 (2020) .4/53
2. f
, ,
fC .
3.
f *
f x x ,
f
,f , 0
2 ,f 2
.
4. 3
f x x ,x .
5. ,f
3
y x ,x 1 ,
1,1 .
,
t t t
, t
B
fC ,f
x, 0t 3 sec.
6.
( )
fC 1,f 1
f ,0 ,
x.
1. :
1
3x 1 0 x .
3
1
x ,
3
:
x x
3x 1 0 2 2 3x 1, ,
1
,
3
, x
2 3x 1 .
1
x
3
:
x
g x 02 3x 1
1 1
x x
3 3
,
x 1
g x 2 3x 1 , x ,
3
.
g 1 2 3 1 0 3
g 3 2 3 3 1 0 .
1
x ,
3
x
g x 2 ln 2 3
2x
g x 2 ln 2 0 .
g x 0
1 2 3
1
, , , ,
3
1 2 3
g 1 2,
2 3, .
g
1 2, 2 3, x
g x 2 ln 2 3.
1 2g g 2 3g g
g
Rolle 1 2,
2 3, , 1 1 2,
2 2 3, 1g 0
2g 0 .
g 1 2,
g
1 2,
2x
g x 2 ln 2
1 2g g 0
g
Rolle 1 2, ,
1 2, g 0 ,
2x
g x 2 ln 2 0
1
x
3
. g x 0,
x
2 3x 1,
, ,
1x 1 2x 3.
2.
*
x f x 0 f
, f
( )
.
f
,0 0, .
:
x 0
f x 2 1
f 4 . . 3
56. _______________________________ ______________________________
116 (2020) .4/54
f
f
,0
0,
, f
0x 0, fC
M 0,f 0 ( f 0 0 ).
M 0,0 fC .
3. f
fC M ,f
2 ,f 2 :
f 2 f
f f
2
1 12
2 3
3
0
2 3 2 1 3
3 1 2 : 1 . ,
2 2 1 :
1
3 1 2 g 0
3
( 1)
1, f x x , x f x 1
, fC : y 1
, .
3
3
f x x , x .
4. t 0, t t ,
: t
t c e , t 0, .
0 1 c 1 1 c 1, t
t e ,t 0.
x 1, 2
f x 3x ,
3
A , : : y f f x
3 2 2 3
y 3 x y 3 x 2
,
,0 , : 2 3 2
0 3 2
3
.
t , t :
t
t e
t2 2
t t t e
3 3
.
t 0, , ,
t,
t t2 2
t e e . ./ sec
3 3
,
, 0t 3 sec,
32
3 e . ./ sec
3
.
5. x 2
f x 3x ,
fC f
1,f 1 , : y f 1 f 1 x 1 .
: f 1 1 2
f 1 3 1 3,
y 1 3 x 1 y 3x 2.
: y 3x 2 .
:
3
f x x , x ,0
h x 3x 2,x ( h
: y 3x 2 fC )
x 0,x
(
: y 0,( x x) )
:
f x h x , x ,0 . :
3 3
f x h x x 3x 2 x 3x 2 0
x ,0 x ,0x ,0
3 3
x 3x 2 0 x 4x x 2 0
x ,0 x ,0
2
x x 4 x 2 0
x ,0
x x 2 x 2 x 2 0
x ,0
x 2 x x 2 1 0
x ,0
57. _______________________________ ______________________________
116 (2020) .4/55
2
x 2 x 2x 1 0
x ,0
x 2, x 1
x 2
x ,0
f ,h ,
2, 8 .
:
h x x ,x .
:
2
h x x 3x 2 0 x
3
.
h,
2
,0
3
.
:
f x x , x ,0 .
: 3
f x x x 0 x 0.
f,
0,0 .
,
f,h,
6.
f hC ,C ,C :
1 2 ,
1 1
h fC , C
x 2 x 0 2
2
hC , C
2
x 0 x .
3
:
0
1
2
f x h x dx
0
3
2
x 3x 2 dx
0
4 2
2
1 3
x x 2x
4 2
4 24 21 3 1 3
0 0 0 2 2 2 2
4 2 4 2
0 4 6 4 6 . .
2/3
2
0
x h x dx
2/32/3
2
00
3
0 3x 2 dx x 2x
2
2
2
2
3 2 2 3 4 2 2
2 0 0 . .
2 3 3 2 3 3 3
,
1 2
2 20
6 .
3 3
3
:
1
x
e , x 0
f x 0 , x 0
1
, 0 x 1
lnx
1. f
,1 .
2.
f.
3. f ,
,
.
f
.
4. f
f 1
f .
5.
fC ,
x x
1 : x 1, 2
1
: x
e
2
e
. .
58. _______________________________ ______________________________
116 (2020) .4/56
1. x ,0
1
x
f x e ,
f ,0 ,
. x 0,1
1
f x
ln x
, f 0,1 ,
. :
1
x 0 x 0
1
lim f x lim 0
ln x
x 0
1
y1 x
yx
y1x 0 x 0
lim
x
lim f x lim e lim e 0
f 0 0
,
x 0x 0 x 0
lim f x lim f x 0 limf x 0 ,
x 0
limf x f 0 , f
0x 0.
f
,1 .
2. :
x ,0 ,
1 1 1
x x x
2
1 1
f x e e e
x x
x 0,1 ,
2 2
1 1 1
f x ln x
ln x ln x x ln x
x 0 x 0 x 0
1
f x f 0 1ln xlim lim lim
x 0 x x ln x
2
D.L.H.x 0 x 0 x 0 x 0
1 11
1xx xlim lim lim lim
1ln x xln x
x
f
0x 0 .
1
x
2
2
1
e , x 0
xf x
1
, 0 x 1
x ln x
.
:
x ,0 ,
1 1 1
2x x x
2 2
1 1
f x e x e e
x x
1 1 1 1
3 x x x x
2 3 2 2
1 1 2 1 1
2x e e e e
xx x x x
1 1 1
x x x
3 4 3 4
2 1 1 1 2x 1
e e 2 e
xx x x x
x 0,1 ,
2
22 2
1 1
f x xln x
xln x xln x
2 2
22
1
x ln x x ln x
x ln x
2
22
1 1
ln x x 2ln x
xx ln x
2
22
1
ln x 2ln x
x ln x
1
x
4
2
22
2x 1
e , x 0
x
f x
ln x 2lnx
,0 x 1
xln x
.
3.
1
x
2
2
1
e , x 0
xf x
1
, 0 x 1
x ln x
. :
x ,0 ,
1
x
2
1
f x e 0
x
x 0,1 , 2
1
f x 0
xln x
f 0, f
,1 .
1
x
4
2
22
2x 1
e , x 0
x
f x
ln x 2lnx
,0 x 1
xln x
.
x ,0 :
1
x
4
2x 1
f x e
x
:
59. _______________________________ ______________________________
116 (2020) .4/57
1
x
4
2x 1
1e 0f x 0
xx
2x 0 x 0
1
x
4
2x 1
1e 0f x 0
x 0x
2x 0 x 0
1
x
4
2x 1
1e 0f x 0
xx
2x 0 x 0
x 0,1 :
22
ln x ln x 2
f x
xln x
.
22
x ln x 0
x 0,1
lnx: 0,
x 1 lnx 0
1
ln x 2 2
ln x 2 0 ln x 2 e e x e
x
e : 0,
lnx 2 2
lnx 2 0 lnx 2 e e x e
1
2
ln x 2 0 0 x e
x 0 2
e 1
ln x
ln x 2
f x 0 2
x 0,e
f x 0 2
x e ,1 .
f x f .
x 1/ 2 0 2
e 1
f x
f x 4 3 3 4
f
:
f
1
,
2
2
e ,1
f
21
,0 , 0,e
2
f 1
1
x
2
2
2x e
1
1
22
1
f e e
2
2
2
1 1
f e
2ln e
fC :
21
A ,e
2
2 1
B e ,
2
.
:
f ,1 .
1
0
x 1 x 1
1
lim f x lim
ln x
,
x 1
fC .
1
x
x x
lim f x lim e 1,
y 1 fC
.
f
1, 2 , 3
x 1 / 2 0 2
e 1
f x
f x
f x 8 2
e
7 7 1 / 2
8
fC .
4. f 1 1 ,
fD ,1 , f
1
x
y
O
1
60. _______________________________ ______________________________
116 (2020) .4/58
1
f f ,1 f
.
x 1
lim f x
x
lim f x 1,
, ,1 , f
xx 1
f ,1 lim f x , lim f x ,1 .
1
f
f x y , x , fx D ,1
1
f
y D f ,1 ,1 .
x ,0
1
x
f x e
f : ,0
f ,0 xx 0
f ,0 lim f x , lim f x 0,1
2
:
1
x
f x y
e yx ,0
x 0, y 0,1
y f ,0 0,1
11
xln y
ln yx
x 0, y 0,1 y 0,1
x 0,1
1
f x ,
ln x
f : 0,1
f 0,1 x 1 x 0
f 0,1 limf x , lim f x ,0
2
:
f x y 1
y
x 0,1 ln x
x 0,1 ,y ,0y f 0,1 ,0
1
y
1
ln x
x ey
y ,0x 0,1 ,y ,0
f 0 0, 1
f 0 0.
:
1
1
y
1
, y 0,1
ln y
f y 0 , y 0
e , y 0
.
f
:
1 1
1
x
1
,x 0,1
lnx
f : ,1 , f x 0 ,x 0
e ,x 0
1
f f .
5.
fC , x x
1 : x 1, 2
1
: x
e
1 1
0e e
1 1 0
1
0 ef x 0 x 1,0
1
f x 0 x 0, 1 0
e
1
0 e
1 0
E f x dx f x dx f x dx
f x dx f x dx
f x dx f x dx.
.
x 1,0 :
f ,1
1
1 x 0 f 1 f x f 0 e f x 0
2
1
f x ,
e
1
f x
e
x 1, :
0
0 0
1 1
1
1 1 1
f x dx dx x
e e e
0
1
1
f x dx : 1
e
1
x 0,
e
:
f ,1
1
1 1
0 x f 0 f x f
e e
1 1
0 f x 1 f x 1
1 ln eln
e
2
f x 1
1
x
e
, :
61. _______________________________ ______________________________
116 (2020) .4/59
11 1
ee e
00 0
1 1
e e
0 0
1
f x dx 1 dx x
e
1 1
f x dx f x dx : 2
e e
1 2
1
0
e
1 0
1 1 2 2
f x dx f x dx E . .
e e e e
4
f : 0, : f 0 0
2
x
f x x x
lim 1
x 1
.
1. 2
f x x , x 0, .
2. ,f , 0
,
:y x 1 .
3.
fC y x 1 ,
x 0 x 1,
1. 0y y
2. y kx
.
1.
2
f x x x
g x ,x 0, ,
x 1
2
f 0 0 0 0
g 0 0
0 1 1 x
lim g x 1.
. x x 1,
x .
2
A x f x x x
1
1 1 0x x ... x , 0, ,x
x (
A x ,
A x 0 , g x 0
x x
lim g x lim 0 0 1, ).
2
x x
f x x x
lim g x lim
x 1
1
11 0
x x x
x x ... x
lim lim lim x
x 1 x
:
1 1 0 ,
1
x x x
, 0x
lim g x lim lim x
, 0x
,
x
lim g x 1.
1 0 ( N ),
0
0 0
x x x
x
lim g x lim lim 0
x x
.
,
x
lim g x 1.
1. 1, :
1
1
1
x x
x
lim g x 1 lim 1 1
x
,
2
0 0
2
0
A x x f x x x x
f x x
.
, 2
0 0f 0 0 0 0 0 .
2
f x x ,x 0, .
2.
:
1
2
, :
d , :x y 1 0
2
22
1f 1
21 1
2 2
B Bx x y y
1 1 2
62. _______________________________ ______________________________
116 (2020) .4/60
2 21 1
1 1
2 2
2
1 0
3 0
21
1
2
0
1 1
2 1
2 2
.
:
1 1
0 0
2 2
1 1
0 0
2 2
1 1
0 0
2 2
E 0,
:
1
0,
2
,
1
,
2
,
0
1
x
2
,
2
1 1 1 1 3
1 . .
2 2 2 2 8
0
1 1
,f
2 2
0
1 1
, .
2 4
3.
To :
f
y x 1
x 0 , x 1 :
2
1 1
2
0 0
x x 1 0
13 0
2
0
f x x 1 dx x x 1 dx
x x 1 dx
13 2
0
x x 1 1 5
x 1 . .
3 2 3 2 6
1.
,
1 1 1
O 1 1
2 2 2
.
1 5
O
2 2 12
,
x x
.
( )
0y y
x x
01 y 0 .
0y y y y ,
00,y .
M
0y y , y x 1,
:
0 00
0 0
0 0
y y y yy y
M y 1,y
y x 1 x y 1y x 1
63. _______________________________ ______________________________
116 (2020) .4/61
1E , , :
1 0 0
1 1
E y 1 y 1
2 2
2 2
0 0
1 1
y 1 y 1
2 2
.
0y 1,0 1
E
E
2
.
:
2 2
1 0 0
E 1 1 5 5
E y 1 y 1
2 2 2 6 6
0 0
5 5
y 1 y 1
6 6
0 0
5 5
y 1 y 1
6 6
0
5
y 1 1,0
6
,
0
5
y 1 1,0
6
.
fC
y x 1, x 0
x 1,
5
y 1
6
.
2. O
2
,
y kx
x x .
k 0 .
y kx y x 1
:
k 1
1
y 1
y x 1 1 k
y kx kx x 1 1
x
1 k
1
y
1
x
, 1
1
1
k 1 k
1
d ,y y
1
,
2
. :
E 1 5
d , y y
2 2 12
1 1 5 6 6 1
1 1 1
2 1 12 5 5 5
1
y x
5
fC
y x 1, x 0
x 1, .
5
f : 0, ,
0,
64. _______________________________ ______________________________
116 (2020) .4/62
, , , .
1.
,
fC .
2
4 cm .
2. ,
2
2
16
P , 0.
3.
i. ,
2
2
16
P x x , x 0
x
,
.
ii. x
OB OAB
,
OA,OB . ;
4.
P.
5. :
4 4
P P ,x 0,1
x 1 e
.
1. fC 0,
O ,
O , A , , ,
x 0, : 0 f x : 1 .
OB
,
y x, . OB
,
0
, : y x .
fC OB
0x 0,
f x x f x x 0 g x 0 .
g x f x x, x 0, . g
0, ,
. , g 0 f 0 0,
1 g f f 0,
1 , g 0 g 0
g
Bolzano 0, ,
0x 0,
0g x 0. fC OB
0x 0, .
2. O
2
4 cm :
4
4 4
O
2 2
B O B OOB x x y y
2 2 2 2
0 0
2
2 2
2
4 16
.
2
2
16
P , 0
O
0 .
3.
i. 0 ,
2
2
16
P
3
2
2
1
2 32
16
2
4
3
2
2
1 16
16
:
P 0
0
4
16 0 2
x
y
O A( , 0)
(0, ) ( , )
65. _______________________________ ______________________________
116 (2020) .4/63
0
2 2
P 0 0 2
P 0,2 ,
2, ,
0 2,
2
2
16
P 2 2 8 2 2
2
.
ii. (E3i.)
O
2
: min OB 2 2 .
2
4 4
2
2
,
2 . , 2
2 , O
.
4. P
0, P ,
PC 1 : x 0 .
2
2
x 0 x 0
16
lim P x lim x
x
1 : x 0
PC .
y x , , .
2
2 2 x x x
x 02 4
x x
16 16
x x 1
P x x xlim lim lim
x x x
4
4x
16
x 1
16x
lim lim 1 1 0 1
x x
.
1.
2
2x x
16
lim P x x lim x x
x
2
2 2
2 2
2
2
x x
2 2
2 4
16 16x x x xx xlim lim
16 16
x x x 1 x
x x
2
x x x
x 0 2 2
x x
4 4
16 16
x xlim lim
16 16
x 1 x x 1 1
x x
3x
4
16 1 1
lim 0 0
2x 16
1 1
x
0 . 2 : y x
PC .
5. 0,1
4 4
P P
x 1 e
.
1 1
0 x 1 1 x 1 2 1
x 1 2
1 1 4
1 2 4
2 x 1 x 1
,
4
2,
x 1
.
2
2
2 2 2
2
4 4 16 16 16 16
e e
16e e e e4
ee
, e 2,
:
4
P P e
e
4 4 4
P P P P e
x 1 e x 1
x 0,1 x 0,1
4
,e 2,
x 1
P 2,
44
x 1e
ex 1
x 0,1 x 0,1
1
4
x 1 4 e
e x , 1
e
x 0,1
4 e
x , 1
e
66. _______________________________ ______________________________
116 (2020) .4/64
:
1
f,g,G: 1,2
h: 1,2 :
f , 1,2
.
g .
G g.
f(x) - f(1)
h(x) =
x-1
.
:
i)
f(x) - f(1)
f (x) >
x-1
, x 1,2 .
ii) h 1,2 .
iii) f(x) (f(2) - f(1))(x-1) + f(1) , x 1,2
iv)
2
1
f(1)+f(2)
f(x)dx<
2
v)
2 2
1 1
(2x-3)g(x)dx=G(1)+G(2)-2 G(x)dx .
vi)
2
1
(2x-3)g(x)dx>0 .
i) 1 x 2 . f -
1,x ,
f(x)-f(1)
f( )=
x-1
f , f´ -
1,2 :
ii) h
2
f (x)(x-1) - (f(x) - f(1))
h (x) = , x 1,2
(x-1)
(i) :
f x x 1 f x f 1 0, x 1,2
h (x) > 0, x 1,2
h 1,2 ,
1,2 .
iii) x=1 x=2 . h
1,2 , :
1< x < 2 h(x) < h(2) f(x) < (f(2)-f(1))(x-1)+f(1).
iv) (iii)
1,2 , :
2 2
1 1
f(x)dx < [(f(2) - f(1))(x-1) + f(1)]dx
2 2
1 1
= (f(2) - f(1)) (x-1)dx+ f(1)dx
22
1
x
= (f(2) - f(1)) - x + f(1)
2
(f(2) - f(1)) f(1) + f(2)
= + f(1) =
2 2
.
v) G'(x)=g(x) x 1,2 , :
2 2
1 1
(2x-3)g(x)dx = (2x-3)G (x)dx
22
1 1
= (2x-3)G(x) -2 G(x)dx
2
1
=G(1)+G(2)-2 G(x)dx .
vi) G'=g g , G
. (iv) :
2
1
G(1) + G(2)
G(x)dx <
2
2
1
G(1)+G(2)-2 G(x)dx >0
(v) 2
1
(2x-3)g(x)dx > 0 .
2
f:
.
i) 0x
0f (x ) = 0 .
ii) f 0x
.
iii) , 0< x < , -
fC
( ,f( )) ( ,f( )), :
x -
lim f(x)=+
x
lim f(x)=+
iv)
f(x+ 2020) = f(x) .
i) f ,
1 2f(x ) = f(x ) .
1 2x x . f
, -
Rolle
1 2x ,x . 0 1 2x x ,x
0f (x ) = 0 .
ii) H f f -
. , 0 0x < x f (x) < f (x ) = 0
0 0x > x f (x) > f (x ) = 0
f 0x , -
0x .
iii) A B
fC
68. 116 (2020) .4/66
Ky Fan
,
,
,
2019.
,
.
( .112) -
Jensen. : -
f I ,
:
1 1 2 2 n n 1 1 2 2 n nf x x x f x f x f x 1
1 2 nx ,x , ,x I
1 2 n, , ,
1 2 n 1. (1)
1 2 nx x x f -
. ,
Jensen
Ky Fan (1914-2010) , -
Santa Barbara
( . . ). ,
, 1961 Beck-
enbach E.F, Bellman R. “Inequalities” Berlin, Springer
1961 : 1 2 na ,a , ,a n 2
1
0,
2
.
1 2 n
n
a a a
A
n
1
n
n 1 2 nG a a a .
:
1 2 n
n
1 a 1 a 1 a
A
n
1
n
n 1 2 nG 1 a 1 a 1 a
1 2 n1 a ,1 a , ,1 a .
Ky Fan
1 2 na ,a , ,a :
n n
n n
G A
G A
1 2 na a a
f
1 x
f x ln
x
.
.
1
0,
2
,
22
1 2x
f x 0
x 1 x
1
x 0,
2
.
Jensen -
*
1 2 n
1
, n
n
1 2 n
1
x ,x , ,x 0,
2
.
’
1 2 n1 2 n
f x f x f xx x x
f
n n
1 2 n
1
x ,x , ,x 0,
2
, :
1 1 2 n
n
1 2 n
1
1 2 nn
1 2 n
x x x
x x x n
1 x 1 x 1 x
1 x 1 x 1 x
n
n n
n n
G A
G A
-
1 2 nx x x f
.
Ky Fan
1.
1
a , b 0,
2
,
2 2
1 a 1 ba b
a b 2 a b
2
2
a ba b
1 a 1 b 2 a b
70. ----------------------------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------------------------------------------
116 (2020) .4/68
2 2 2
2 2 2
2 2 2
A
3
2 2 2
A
2 2 2
3
1
A
2 2 2
2 2 23
2 2 2
A 3
1
A2 2 2
2 2 2
5. :
(i)
1 1
0 a , 0 b
2 2
,
1 a 1 b a b
1 b 1 a b a
(ii)
1 1 1
0 a , 0 b , 0 c
2 2 2
,
1 1 1
1 a 1 b 1 c
1 a 1 b 1 c
1 1 1
a b c
a b c
(i) ( 1) :
2
2
a bab
1 a 1 b 2 a b
:
2 2
1 a 1 b a b
1 a 1 b ab
2 2 2 2
1 a 1 b a b
2 2
1 a 1 b 1 a 1 b ab ab
1 a 1 b a b
1 b 1 a b a
(ii) :
1 1 1
1 a 1 b 1 c
1 a 1 b 1 c
1 b 1 c 1 c 1 a
1 c 1 b 1 a 1 c
(i) :
1 a 1 b 1 b 1 c 1 c 1 a
3
1 b 1 a 1 c 1 b 1 a 1 c
a b b c c a
3
b a c b a c
1 1 1
a b c
a b c
.
6.
n
n
1 2 n n
1 1 1 2 1
2 1 2 1 2 1 1 n 1 2
:
n
2 n
n
1 2 n
n
2 n
1 1 1
1 1 1 2 2 2
2 1 2 1 2 1 1 1 1
1 1 1
2 2 2
Ky Fan :
2
1 2
2
1 1 1
1 1 1 2 2 2
1 1 12 1 2 1 2 1
1 1 1
2 2 2
n
n
n
n
n
n
n
n
1
1
1 2
12 1
2 12
1 1 n 1 21
1 2n
12 1
2
7. :
2 2 2 2
2 2
x x
2 x 2 x
2 2
xx x1 x 1
22
.
:
2 2 2 2
2 22 2
x x
x x
2 2
xx 2 1 x 12 x 2
22
2 2
2 2
1 1 x
x
2 2 2
1 1 x
1 x 1
2 2 2
2 2
2 2
x
x
2
1 1 x
1 x 1
2 2 2
2 21 1 x
x ,
2 2 2
1
0,
2
, -
Ky Fan -
: 2 21 1 x
x , x k , k
2 2 2
.
, -
:
2 4
x 4k , x 4k , k
3 3
.
71. 116 (2020) .4/69
Ceva
,
. , .
( 3
) . ,
. -
,
.*
1
2
, ,
, , ( 1).
1 1 1
, ,
x y z
, ,
1 2 3
1 2 3
, , ,
, , ( ).
1.
xyz 1
x 1 y 1 (z 1)
:
1 2 3 1 2 3( )
1
1
y z x
1 ( )
y 1 z 1 z 1 x 1 x 1 y 1
*
Ceva
1 xyz
x 1 y 1 z 1
Ceva
, ,
( 2), :
1.
:
( )( ) ( ) ( )
( ) ( )
.
( ) ( )
( ) ( ) ( )
1.
( )
. , ,
( 2)
.
2.
, , ,
2
x 1 y 1 (z 1)
.
: [ 1],
Ceva xyz=1.
3.
, , ,
.
4
, , .
: x,y,z>0
xyz=1, x 1 y 1 z 1 8 (
x=y=z=1). , [ 2]
2
8 4
x y z 1 , , ,
.
4.
, , ,
2
1 2 32 .
:
1 21 1
, ,
x 1 y 1
3 1
.
z 1
Ceva*