2009 年上海卢湾中考数学真题及答案
(满分 150 分,考试时间 100 分钟)
考生注意:
1.本试卷含三个大题,共 25 题;
2.答题时,考生务必按答题要求在答题纸规定的位置上作答,在草稿纸、本试卷上答题一
律无效.
3.除第一、二大题外,其余各题如无特别说明,都必须在答题纸的相应位置上写出证明或
计算的主要步骤.
一、选择题:(本大题共 6 题,每题 4 分,满分 24 分)
【下列各题的四个选项中,有且只有一个选项是正确的,选择正确项的代号并填涂在答题
纸的相应位置上.】
1.计算 3 2
)a 的结果是()
(
A. 5a
B. 6a
C. 8a
D. 9a
2.不等式组
A.
x
1
,
的解集是()
1 0
x
2 1
x
B. 3x
x
x
3.用换元法解分式方程
1
整式方程,那么这个整式方程是()
1
3
x
x
3x
C. 1
1 0
时,如果设
1x
D. 3
y
,将原方程化为关于 y 的
1x
x
A. 2
y
y
3 0
B. 2 3
y
y
1 0
C. 23
y
y
1 0
D. 23
y
y
1 0
4.抛物线
y
2(
x m
)
2
( m n, 是常数)的顶点坐标是()
n
A.(
)m n,
B.(
)m n
,
C.(
m n,
)
D.(
m n
,
)
5.下列正多边形中,中心角等于内角的是()
A.正六边形
6.如图 1,已知 AB CD EF
B.正五边形
A.
B.
C.正四边形
∥ ∥ ,那么下列结论正确的是()
C.正三边形
AD BC
DF CE
CD BC
BE
EF
C.
D.
BC DF
CE
AD
CD AD
AF
EF
二、填空题:(本大题共 12 题,每题 4 分,满分 48 分)
【请将结果直线填入答题纸的相应位置】
1
7.分母有理化:.
5
A
C
E
B
D
F
图 1
8.方程
x 的根是.
1 1
9.如果关于 x 的方程 2
x
1
10.已知函数
( )
f x
( k 为常数)有两个相等的实数根,那么 k .
x
k
0
,那么 (3)
f
.
x
11.反比例函数
y
图像的两支分别在第象限.
1
2
x
12.将抛物线
y
2
x 向上平移一个单位后,得以新的抛物线,那么新的抛物线的表达式是.
13.如果从小明等 6 名学生中任选 1 名作为“世博会”志愿者,那么小明被选中的概率是.
14.某商品的原价为 100 元,如果经过两次降价,且每次降价的百分率都是 m ,那么该商
品现在的价格是元(结果用含 m 的代数式表示).
15.如图 2,在 ABC△
中, AD 是边 BC 上的中线,设向量,
A
AB a
BC b
=
,b
,那么 AD
表示向量 AD
如果用向量 a
16.在圆O 中,弦 AB 的长为 6,它所对应的弦心距为 4,那么半
径OA .
17.在四边形 ABCD 中,对角线 AC 与 BD 互相平分,交点为
O .在不添加任何辅助线的前提下,要使四边形 ABCD 成为矩形,
还需添加一个条件,这个条件可以是.
3
18.在 Rt ABC△
M
, 为边 BC 上的
沿直线 AM 翻
点,联结 AM (如图 3 所示).如果将 ABM△
折后,点 B 恰好落在边 AC 的中点处,那么点 M 到 AC 的距离
是.
三、解答题:(本大题共 7 题,满分 78 分)
19.(本题满分 10 分)
°,
BAC
AB
中,
90
C
D
图
B
A
B
M
图 3
C
计算:
2
a
a
2
1
(
a
1)
a
2
1
2
a
1
2
a
.
20.(本题满分 10 分)
解方程组:
y
2
1
x
,
2
x
xy
2 0
.
①
②
21.(本题满分 10 分,每小题满分各 5 分)
如图 4,在梯形 ABCD 中,
(1)求 tan ACB
的值;
(2)若 M N、 分别是 AB DC、 的中点,联结 MN ,求线段 MN 的长.
AD BC AB DC
∥ ,
8
,
BC
60
°,
B
12
,联结 AC .
A D
C图B
22.(本题满分 10 分,第(1)小题满分 2 分,第(2)小题满分 3 分,第(3)小题满分 2
分,第(4)小题满分 3 分)
为了了解某校初中男生的身体素质状况,在该校六年级至九年级共四个年级的男生中,分别
抽取部分学生进行“引体向上”测试.所有被测试者的“引体向上”次数情况如表一所示;
各年级的被测试人数占所有被测试人数的百分率如图 5 所示(其中六年级相关数据未标出).
0
1
1
1
2
2
3
2
4
3
5
4
6
2
7
2
8
2
9
0
10
1
次数
人数
表一
八年
25%
九年
30%
根据上述信息,回答下列问题(直接写出结果):
(1)六年级的被测试人数占所有被测试人数的百分率是;
(2)在所有被测试者中,九年级的人数是;
(3)在所有被测试者中,“引体向上”次数不小于 6 的人数所
占的百分率是;
(4)在所有被测试者的“引体向上”次数中,众数是.
23.(本题满分 12 分,每小题满分各 6 分)
已知线段 AC 与 BD 相交于点O ,联结 AB DC、 ,E 为OB
的中点, F 为OC 的中点,联结 EF (如图 6 所示).
(1)添加条件 A
求证: AB DC
.
(2)分别将“ A
记为②,“ AB DC
③,以①为结论构成命题 2.命题 1 是命题,命题 2 是命题(选择“真”或“假”填入空格).
24.(本题满分 12 分,每小题满分各 4 分)
D
”记为③,添加条件①、③,以②为结论构成命题 1,添加条件②、
”记为①,“ OEF
, OEF
B E
七年
25%
六年
OFE
OFE
图 5
图 6
O
D
D
F
C
A
,
”
在直角坐标平面内,O 为原点,点 A 的坐标为 (1 0), ,点C 的坐标为 (0 4), ,直线CM x∥
轴(如图 7 所示).点 B 与点 A 关于原点对称,直线 y
(b 为常数)经过点 B ,且
x b
是等腰三
与直线CM 相交于点 D ,联结OD .
(1)求b 的值和点 D 的坐标;
(2)设点 P 在 x 轴的正半轴上,若 POD△
角形,求点 P 的坐标;
(3)在(2)的条件下,如果以 PD 为半径的圆 P 与
圆O 外切,求圆O 的半径.
25.(本题满分 14 分,第(1)小题满分 4 分,第(2)
小题满分 5 分,第(3)小题满分 5 分)
已知
AD BC P
线段 BD 上的动点,点Q 在射线 AB 上,且满足
3
, ∥ , 为
ABC
2
,
BC
AB
90
°,
4
3
2
1
B
O
y
C
D
M
A
1
图 7
x
(如图 8 所示).
PQ AD
AB
PC
AD ,且点Q 与点 B 重合时(如图 9 所示),求线段 PC 的长;
(1)当
2
(2)在图 8 中,联结 AP .当
AD ,且点Q 在线段 AB 上时,设点 B Q、 之间的距离
3
2
△
为 x , APQ
PBC
△
S
S
y
,其中 APQ
S△ 表示 APQ△
的面积, PBC
S△ 表示 PBC△
的面积,求 y 关
于 x 的函数解析式,并写出函数定义域;
(3)当 AD AB
,且点Q 在线段 AB 的延长线上时(如图 10 所示),求 QPC
的大小.
A
Q
B
D
P
A
D
P
图
C
B(Q 图
A
D
P
图
C
B
Q
C
参考答案
一.选择题:(本大题共 6 题,满分 24 分)
1.B;2.C;3.A;4.B;5.C;6.A.
二.填空题:(本大题共 12 题,满分 48 分)
7.
;
;
8. 2x
解:由题意知 x-1=1,解得 x=2.
9.1
4
;
10. 1
2
;
y
x
11.一、三;
2 1
;
12.
解:由“上加下减”的原则可知,将抛物线 y=x2-2 向上平移一个单位后,得以新的抛物线,
那么新的抛物线的表达式是,y=x2-2+1,即 y=x2-1.
故答案为:y=x2-1.
13. 1
6 ;
解:因为从小明等 6 名学生中任选 1 名作为“世博会”志愿者,可能出现的结果有 6 种,选
中小明的可能性有一种,所以小明被选中的概率是 1/6.
;
14.
解:第一次降价后价格为 100(1-m),第二次降价是在第一次降价后完成的,所以应为 100
(1-m)(1-m),
即 100(1-m)2.
100
1(
m
2)
a
15.
b
1 ;
2
解:因为向量 AB=a,BC=b,根据平行四边形法则,可得:AB=a,BC=b,AC=AB+BC=a+b,又
因为在△ABC 中,AD 是 BC 边上的中线,所以
16. 5 ;
17. AC BD (或
解:∵对角线 AC 与 BD 互相平分,
∴四边形 ABCD 是平行四边形,
ABC
等);
90
要使四边形 ABCD 成为矩形,
需添加一个条件是:AC=BD 或有个内角等于 90 度.
18. 2 .
三.解答题:(本大题共 7 题,满分 78 分)
a
2)1
(2
)1
a
1
a
19.解:原式=
)(1
(
a
1
)1
1
a
a
(
··········································· (7 分)
y
=
=
a
a
1
1
a
1
a
将③代入②,得
2
························································································· (1 分)
1
a ··································································································· (1 分)
1
= 1 .··································································································· (1 分)
1 x
,③······························································· (1 分)
20.解:由方程①得
2 2
(
xx
x
,··········································· (1 分)
2
2
0
x
x
,······························································ (2 分)
2
1
x
,
,···································································(3 分)
2
1
2
x
y
,
,···························· (2 分)
代入③,得 1
2
1
2
x
x
,
,
所以,原方程组的解为 1
2
··················································· (1 分)
3
0.
y
y
;
2
1
,垂足为 E .············································ (1 分)
AE
BC
60
B
,
8
60
cos
21.解:(1)过点 A 作
在 Rt △ ABE 中,∵
B
∴
,··················································· (1 分)
整理,得
x
解得 1
x
分别将 1
8AB ,
4
2)1
3
,
cos
AB
BE
0
0
y
2
AE
AB
12BC
sin
B
,∴
60
sin
8
.···················································(1 分)
8EC .···································································· (1 分)
34
∵
在 Rt △ AEC 中,
tan
ACB
.···································· (1 分)
∵ M 、 N 分别是 AB 、 DC 的中点,∴
MN
8
.········(2 分)
22.(1) %20 ;······················································································(2 分)
(2) 6 ;····························································································(3 分)
(3) %35 ;······················································································· (2 分)
(4)5 .···························································································· (3 分)
AD
2
BC
4
12
2
,
OF
OFE
OEF
23.(1)证明:
OE
∴
∵ E 为OB 的中点, F 为OC 的中点,
∴
∴
∵
OB 2
OE
OB
OC
A
D
AOB
OC 2
DOC
OF
.··············································· (1 分)
,
.···································································· (1 分)
,
,
.···································································· (1 分)
AE
EC
AB
34
8
3
2
60
,
B
DC
60
BC
B
DF
BC
(2) 在梯形 ABCD 中,∵
DCB
∴
过点 D 作
∵
在 Rt △ DCF 中,
FC
∴
AD // ,∴四边形 AEFD 是平行四边形.∴
cos
,垂足为 F ,∵
cos
4AD
DC
.∴
DCF
.
FC
4
DFC
8
EC
EF
,
.········································································· (1 分)
AEC
AD
60
DF
AE //
90
,∴
EF
.······················ (1 分)
4
,······················· (1 分)
.
∴△ AOB ≌△ DOC .··············································································(2 分)
AB
.························································································· (1 分)
(2)真;····························································································(3 分)
假.··································································································· (3 分)
DC
24.解:(1)∵点 A的坐标为 (1 0), ,点 B 与点 A 关于原点对称,
y
∴点 B 的坐标为 ( 1 0)
∵直线
∵点C 的坐标为 (0 4), ,直线
∵直线
bx
1 x
y
0
1
, .··································································(1 分)
b ,得 1b .····························(1 分)
经过点 B ,∴
CM // 轴,∴设点 D 的坐标为 ( 4)x, .········ (1 分)
x
与直线CM 相交于点 D ,∴ 3x .∴ D 的坐标为 (3 4), .…(1 分)
5OD .················································· (1 分)
时,点 P 的坐标为 (6 0), ;········································ (1 分)
时,点 P 的坐标为 (5 0), ,·········································(1 分)
(2)∵ D 的坐标为 (3 4), ,∴
当
当
当
∴
PD
PO
PO
OD
OD
PD
(
x
x
5
5
时,设点 P 的坐标为 ( 0)x,
2
)3
2
4
,得
25x
6
综上所述,所求点 P 的坐标是 (6 0), 、 (5 0), 或
(3)当以 PD 为半径的圆 P 与圆O 外切时,
( x
)0
,
,∴点 P 的坐标为
25(
6
0)
, .
25(
6
0)
, .············ (1 分)
若点 P 的坐标为 (6 0), ,则圆 P 的半径
∴圆O 的半径 1r .······································································(2 分)
若点 P 的坐标为 (5 0), ,则圆 P 的半径
∴圆O 的半径
.···························································· (2 分)
525 r
52PD
5PO
6PO
5PD
,圆心距
,圆心距
,
,
25.解:(1)∵
综上所述,所求圆O 的半径等于1或
BC
,∴
.∴
AD // ,∴
ABD
45
PBC
AB
AD
45
AD
ABC
PQ
PC
PCB
BPC
2
AB
90
AD
AB
90
PBC
,
∵
∵
∵
∴
∴
.
525
DBC
.∴
ADB
ADB
.···················································(1 分)
DBC
.
ABD
.
,点Q 与点 B 重合,∴
.·······························································(1 分)
.············································································(1 分)
PQ
PC
PB
.
23
2
45
cos
3
cos
C
AB
,垂足分别为 E 、 F .····················· (1 分)
90
.∴四边形 FBEP 是矩形.
.····················· (1 分)
BC
PF
BEP
.
PC
BC
FBE
PE
,
BF
PF //
AD
.∴
AD
AB
.
PF
BF
3
4
2AB ,∴
PF
PE
2 ,
x
QB
3BC ,∴
(2)过点 P 作
PFB
∴
∴
在 Rt △ BPC 中,
PE
PF // ,
BC
AD // ,∴
BC
3AD
2
AB
∵
∵
,
∵
AQ
S
S
APQ
PBC
∴
.················································ (1 分)
S
△
APQ
x
2
2
PF
,
S
△
PBC
3
2
PE
.
2 x
4
,即
y
2 x
4
.···················································· (2 分)
.·························································· (1 分)
AB
PN // ,
BC
PN
AD
BN
AB
,垂足分别为 M 、 N .
AD
AB
BN
PN
PM
PM
.∴
,
.
90
MPN
.·············· (1 分)
函数的定义域是 0 ≤ x ≤
7
8
PN
易得四边形 PNBM 为矩形,∴
PM
BC
,
(3)过点 P 作
∵
∵
∴
又∵
∵
即
,∴
.∴
BC
AD
AB
PMC
PN //
AD
PN
PQ
PM
PC
90
PNQ
AD // ,∴
PQ
PC
CPM
QPN
90
MPN
,∴
90
QPC
.··········································································(1 分)
,∴ Rt △ PCM ∽ Rt △ PQN .··············· (1 分)
.···································································· (1 分)
.······················································· (1 分)
QPM
QPM
CPM
MPN
QPN
,
90