书书书
!"#$%&'()*+,-./ 2020 1
!、"#$%&:
! " 1 2 3 4 5 6 7 8
# $ C D A B D C D B
'、(#$%&:
! " 9 10 11 12
# $ BD AB BCD ABC
)、*+&:
13. y2
12 - x2
24 = 1 14. 2
3 - 2n 15. 4,槡8 3 16. 槡8 85
85
,、-.&:
17. (10 %)
&':①(%):
∵ m2 - n2 = 1
∴ m2 = n2 + 1 1 %************************
∴ m4 - n4 = (m2 + n2 )(m2 - n2 ) 3 %****************
= m2 + n2
= n2 + 1 + n2
= 2n2 + 1 4 %*********************
∴ m4 - n4 = 2n2 + 1 +, 5 %********************
②-.):
∵ m4 - n4 = 2n2 + 1
∴ m4 = n4 + 2n2 + 1
= (n2 + 1)2 8 %**********************
∴ m2 = n2 + 1
/ m2 - n2 = 1 9 %************************
∴ m2 - n2 = 1 +,.
01,m4 - n4 = 2n2 + 1 +,2(.345 m2 - n2 = 1. 10 %******
18. (12 %)
6:(1)①7 m = 0 8,mx2 - mx - 1 = - 1 < 0,9:;+,. 1 %*********
②7 m≠0 8,mx2 - mx - 1 < 0 < x∈R ;+,,=>?@
m < 0
Δ = m2 + 4m{ < 0
6A - 4 < m < 0 4 %***********************
01,BC m 2DEFG5(- 4,0]. 5 %**************(2)H f(x)= mx2 - mx - 1,
①7 m = 0 8,f(x)= - 1 < 0,9:;+,. 6 %************
②7 m > 0 8,f(x)2IJKLM1,?@ f(3)< 0.
/ m < 1
6 ,
∴ 0 < m < 1
6 9 %*************************
③7 m < 0 8,f(x)2IJKLM[,?@ f(1)< 0,/ m - m - 1 = - 1 < 0,
9:+,
∴ m < 0. 11 %**************************
01,BC m 2DEFG5(- ∞ ,1
6 ). 12 %*************
19. (12 %)
6:\$]:^34①(1)∵ a3 = 5,a2 + a5 = 6b2 ,a1 = b1 ,d = q,d > 1
∴ a1 + 2d = 5
2a1 + 5d = 6a1{ d 2 %**********************
6A a1 = 1
d{ = 2 _
a1 = 25
6
d = 5{ 12
(`a) 4 %*****************
∴ b1 = 1
q{ = 2
∴ an = a1 + (n - 1)d
= 2n - 1
bn = b1 qn - 1 = 2n - 1 6 %***********************
(2)∵ cn = an
bn
∴ cn = 2n - 1
2n - 1 = (2n - 1)× (1
2 )n - 1 7 %****************
∴ Tn = 1 + 3 × 1
2 + 5 × (1
2 )2 + …+ (2n - 3)× (1
2 )n - 2 + (2n - 1)× (1
2 )n - 1
∴ 1
2 Tn = 1
2 + 3 × (1
2 )2 + 5 × (1
2 )3 + …+ (2n - 3)× (1
2 )n - 1
+ (2n - 1)× (1
2 )n 8 %**********************
∴ 1
2 Tn = 1 + 2[1
2 + (1
2 )2 + …+ (1
2 )n - 1 ]- (2n - 1)× (1
2 )n 9 %***
= 1 + 2 ×
1
2 [1 - (1
2 )n - 1 ]
1 - 1
2
- (2n - 1)× (1
2 )n
= 3 - (2n + 3)× (1
2 )n
∴ Tn = 6 - (2n + 3)× (1
2 )n - 1 12 %*****************
QRCST!UV#$ W 2 X(Y 6 X)\$R:^34②(1)∵ b2 = 2,a3 + a4 = 3b3 ,a1 = b1 ,d = q,d > 1
∴ a1 d = 2
2a1 + 5d = 3a1 d{ 2
∴ a1 d = 2
2a1 + 5d = 6{ d 2 %***********************
6A a1 = 1
d{ = 2 _ a1 = - 1
d{ = - 2 (`a) 4 %*****************
∴ b1 = 1
q{ = 2
∴ an = a1 + (n - 1)d
= 2n - 1
bn = b1 qn - 1 = 2n - 1 6 %***********************
(2)∵ cn = an
bn
∴ cn = 2n - 1
2n - 1 = (2n - 1)× (1
2 )n - 1 7 %****************
∴ Tn = 1 + 3 × 1
2 + 5 × (1
2 )2 + …+ (2n - 3)× (1
2 )n - 2 + (2n - 1)× (1
2 )n - 1
∴ 1
2 Tn = 1
2 + 3 × (1
2 )2 + 5 × (1
2 )3 + …+ (2n - 3)× (1
2 )n - 1
+ (2n - 1)× (1
2 )n 8 %**********************
∴ 1
2 Tn = 1 + 2[1
2 + (1
2 )2 + …+ (1
2 )n - 1 ]- (2n - 1)× (1
2 )n 9 %***
= 1 + 2 ×
1
2 [1 - (1
2 )n - 1 ]
1 - 1
2
- (2n - 1)× (1
2 )n
= 3 - (2n + 3)× (1
2 )n
∴ Tn = 6 - (2n + 3)× (1
2 )n - 1 12 %*****************
\$b:^34③
∵ S3 = 9,a4 + a5 = 8b2 ,a1 = b1 ,d = q,d > 1
∴ a1 + d = 3
2a1 + 7d = 8a1{ d 2 %************************
6A a1 = 1
d{ = 2 _
a1 = 21
8
d ={ 3
8
(`a) 4 %*******************
∴ b1 = 1
q{ = 2
∴ an = a1 + (n - 1)d
= 2n - 1
QRCST!UV#$ W 3 X(Y 6 X)bn = b1 qn - 1
= 2n - 1 6 %****************************
(2)∵ cn = an
bn
∴ cn = 2n - 1
2n - 1 = (2n - 1)× (1
2 )n - 1 7 %****************
∴ Tn = 1 + 3 × 1
2 + 5 × (1
2 )2 + …+ (2n - 3)× (1
2 )n - 2 + (2n - 1)× (1
2 )n - 1
∴ 1
2 Tn = 1
2 + 3 × (1
2 )2 + 5 × (1
2 )3 + …+ (2n - 3)× (1
2 )n - 1
+ (2n - 1)× (1
2 )n 8 %**********************
∴ 1
2 Tn = 1 + 2[1
2 + (1
2 )2 + …+ (1
2 )n - 1 ]- (2n - 1)× (1
2 )n 9 %***
= 1 + 2 ×
1
2 [1 - (1
2 )n - 1 ]
1 - 1
2
- (2n - 1)× (1
2 )n
= 3 - (2n + 3)× (1
2 )n
∴ Tn = 6 - (2n + 3)× (1
2 )n - 1 12 %*****************
20. (12 %)
6:(1)∵ cde ABEF Pfe
∴ BF∥AE
g BF hi ADE,AE hi ADE
∴ BF∥hi ADE 2 %***********************
g BC∥AD,
jklA:BC∥hi ADE 4 %*******************
g BF∩BC = B,BF,BC hi BCF
∴ hi BCF∥hi ADE
g CF hi BCF
∴ CF∥hi ADE 6 %***********************(2)mI,n A Popqr,s,tuvwopx
A - xyz,y
C(2,2,0),D(0,4,0),F(2,0,4)
∴ →AD = (0,4,0 ),→CD = (- 2,2,0 ),→CF = (0,- 2,4) 8 %**********
z n = (x,y,z)5hi CDF 2]{|M},y
n·→CD = 0
n·→CF{ = 0/ x - y = 0
y - 2z{ = 0
H y = 2,6A x = 2
z{ = 1
∴ n = (2,2,1) 10 %**********
g →AD 5hi AEFB 2]{|M},
QRCST!UV#$ W 4 X(Y 6 X)∴ cos〈n,→AD〉= n·→AD
| n| ·| →AD| = 2
3
∴ hi CDF ~hi AEFB +Riw2EP 2
3 . 12 %******
21. (12 %)
6:z c = kx2 (k≠0) 1 %*************************
7P 300
8,z4CP x1 ,y
- x1 + b = 300
kx2
1{ = 1800 ① 2 %******************
7P 320
8,z4CP x2 ,y
- x2 + b = 320
kx2
2{ = 200 ② 3 %******************
,①②6A k = 2,b = 330
∴ c = 2x2 ,p = - x + 330 5 %**********************
(1)z x 42+P y
,h+P s
,y
y = 800 + 2x2 6 %*************************
∴ s = y
x = 800 + 2x2
x
= 800
x + 2x≥2 800
x ·2槡x = 80 7 %****************
77800
x = 2x,/ x = 20 8,s DAE,EP 80.
∴ 20 48,h+,P 80
. 8 %****(2)z x 482P t
,y
t = px - 800 - c
= (- x + 330)x - 800 - 2x2
= - 3x2 + 330x - 800 9 %*********************
H - 3x2 + 330x - 800≥8200
6A 50≤x≤60 11 %***********************
∴ Z 8200
,y2C 50 4,
60 4. 12 %***********************
22. (12 %)
6:(1)!
2a = 4
1
2 × 2c × b 槡= 3
a2 = b2 + c{ 2
,6A b = 1 _ b 槡= 3
∵ b > c,
∴ b 槡= 3
∴ ¡¢ C 2\£5x2
4 + y2
3 = 1. 4 %*****************
(2)
y = kx + m
x2
4 + y2
3{ = 1,¤kA(4k2 + 3)x2 + 8kmx + 4m2 - 12 = 0. 6 %******
QRCST!UV#$ W 5 X(Y 6 X)∵ v¥ l ~¡¢ C ¦=¦]{§Yr M,
∴ m≠0 Δ = 0,
Δ = 64k2 m2 - 4(4k2 + 3)(4m2 - 12)= 0,¨©A 4k2 - m2 + 3 = 0.
z M(x0 ,y0 ),y x0 = - 4km
4k2 + 3 = - 4k
m ,y0 = kx0 + m = 3
m ,
∴ M - 4k
m ,3( )m .
x = 4,
y = kx +{ m6A N(4,4k + m). 8 %****************
ªz«¬r P ?@!,Ie2