2009 年湖南省张家界市中考数学真题及答案
考生注意:本学科试卷共三道大题 25 小题,满分 120 分,考试时量 120 分钟.
一、选择题(本大题共 8 小题,每小题 3 分,满分 24 分)
1.在实数 0, 2 ,
,0.74, π 中,无理数有(
1
3
)
A.1 个
B.2 个
C.3 个
D.4 个
2.用计算器求 32 值时,需相继按“2”,“∧”,“3”,“ ”键,若小红相继按“ ”,“2”,“∧”,“4”,
“ ”键,则输出结果是(
A.4
3.下图所示的几何体的主视图是(
D.16
B.5
C.6
)
)
4.不等式组
A.
1)
7 5(
x
24 6 3
x
4
2
x
x
B.
C.
D.
的解集在数轴上表示为(
)
0
6
A.
0
6
B.
0
6
C.
0
6
D.
5.下列运算正确的是(
)
A. 2
ab
2
2
ab
1
B. tan 45 sin 45
°
1
°
C. 2
x x
x
3
D. 2 3
)a
(
5
a
)
6.下列不是必然事件的是(
A.两直线相交,对顶角相等
B.三角形的外心到三个顶点的距离相等
C.三角形任意两边之和大于第三边
D.两相似多边形面积的比等于周长的比
7.如图, AB CD∥ ,且 1 115
°,
则 E 的度数是(
A.30°
C. 40°
8.为了预防“HINI”流感,某校对教室进行药熏消毒,药品燃烧时,室内每立方米的含药量与时间成正比;
燃烧后,室内每立方米含药量与时间成反比,则消毒过程中室内每立方米含药量 y 与时间t 的函数关系图象
大致为(
B.50°
D.60°
A °,
75
)
)
E
C
1
D
A
B
y
O
y
t
O
t
y
O
y
t
O
t
A.
B.
C.
D.
二、填空题(本大题共 8 小题,每小题 3 分,满分 24 分)
A
.
9. 3 的绝对值为
10.如图, O 是 ABC△
的切点分别为 D E F, , ,若
11.张家界国际乡村音乐周活动中,来自中、日、美的三名音乐家准备在同一节目中依次演奏本国的民族
音乐,若他们出场先后的机会是均等的,则按“美—日—中”顺序演奏的概率是
的内切圆,与边 BC CA AB
A °,则 EDF
, ,
70
O
D
.
B
.
E
F
C
12.将函数
y
3
x
的图象向上平移 2 个单位,得到函数
3
的图象.
13.分解因式 3
a
2
ab
.
14.我市甲、乙两景点今年 5 月上旬每天接待游客的人数如图所示,甲、乙两景点日接待游客人数的方差
大小关系为: 2S甲
2S乙 .
人数
2800
2600
2400
2200
2000
1800
甲
乙
1 2
3 4
5
6
7
8
9 10 日
15.对于正实数 a b, 作新定义: a b b a a b
,在此定义下,若9
x ,则 x 的值为
55
.
16.如图,等腰梯形 ABCD 中, AD BC∥ ,且
AD
1
2
BC
, E 为 AD 上一点, AC 与 BE 交于点 F ,
若 :
AE DE
2 :1
,则
△
△
AEF
CBF
的面积
的面积
.
三、解答题(本题共 9 小题,满分 72 分)
17.(本小题 6 分)
计算
11
2
(5
3)
°
2sin 45
°
1
2 1
A
E D
F
B
C
18.(本小题 6 分)
小明将一幅三角板如图所示摆放在一起,发现只要知道其中一边的长就可以求出其它各边的长,若已知
CD ,求 AC 的长.
2
D
B
A
C
19.先化简,后求值(本小题 6 分)
4
4
2
a
2
2
a
1
2
a
其中
a
2 2
20.(本小题 6 分)
在建立平面直角坐标系的方格纸中,每个小方格都是边长为 1 的小正方形, ABC△
P 的坐标为 ( 1 0)
, ,请按要求画图与作答
的顶点均在格点上,点
(1) 把 ABC△
(2)把 ABC△
(3) A B C
△
绕点 P 旋转180°得 A B C
向右平移 7 个单位得 A B C
与 A B C
△
△
△
.
.
是否成中心对称,若是,找出对称中心 P ,并写出其坐标.
A
B
y
C
P O
x
21.列方程解应用题(本小题 9 分)
“阳黄公路”开通后,从长沙到武陵源增加了一条新线路,新线路里程在原线路长 360Km 的基础上缩短了
50Km,今有一旅游客车和小车同时从长沙出发前往武陵源,旅游客车走新线路,小车因故走原线路,中途
停留 6 分钟.若小车速度是旅游客车速度的 1.2 倍,且两车同时到达武陵源,求两车的速度各是多少?
22.(本小题 9 分)
如图,有两个动点 E F, 分别从正方形 ABCD 的两个顶点 B C, 同时出发,以相同速度分别沿边 BC 和CD
移动,问:
(1)在 E F, 移动过程中, AE 与 BF 的位置和大小有何关系?并给予证明.
(2)若 AE 和 BF 相交点O ,图中有多少对相似三角形?请把它们写出来.
FD
O
A
C
E
B
23.(本小题 9 分)
我市今年初三体育考试结束后,从某县 3000 名参考学生中抽取了 100 名考生成绩进行统计分析(满分 100
分,记分均为整数),得到如图所示的频数分布直方图,请你根据图形完成下列问题:
(1)本次抽样的样本容量是
(2)请补全频数分布直方图.
(3)若 80 分以上(含 80 分)为优秀,请你据此.估算该县本次考试的优秀人数.
.
人数
40
30
20
10
30
20
2
3
5
39.5 49.5 59.5 69.5 79.5 89.5 100
分数
24.(本小题 9 分)
有若干个数,第 1 个数记为 1a ,第 2 个数记为 2a ,第 3 个数记为 3a , 第 n 个数记为 na ,若 1
a ,
1
3
从第二个数起,每个数都等于
.............1.与前面那个数的差的倒数
............
a
(1)分别求出 2
4
a, , 的值.
a
3
a
(2)计算 1
a
2
a
3
a
36
的值.
25.(本小题 12 分)
在平面直角坐标系中,已知 ( 4 0)
A , , (1 0)
B , ,且以 AB 为直径的圆交 y 轴的正半轴于点 (0 2)
C , ,过点C
作圆的切线交 x 轴于点 D .
(1)求过 A B C, , 三点的抛物线的解析式
(2)求点 D 的坐标
(3)设平行于 x 轴的直线交抛物线于 E F, 两点,问:是否存在以线段 EF 为直径的圆,恰好与 x 轴相切?
y
C
2
A
B
D
若存在,求出该圆的半径,若不存在,请说明理由?
张家界市 2009 年初中毕业学业考试数学试卷答案
一、选择题
1.B
二、填空题
2.A
3.B
4.A
5.C
6.D
7.C
8.A
9. 3
10.55° 11.
1
6
12.
y
3
x
5
13. (
a a b a b
)(
)
14. 2
S
甲
2
S 乙
15.16
16.
1
9
三、解答题
17.原式
2 1 2
2
2
1
2 1
2 1
2 1
··························································3 分
2 1
2 ( 2 1)
····················································································· 4 分
2
2 1
2 1
······················································································· 5 分
2 ·············································································································· 6 分
18.解:
BD CD
2
·················································································· 2 分
2
2
BC
,则
AB x
2
x
(2 2)
2
2
2
2 2
2
x
AC
2
(2 )
x
····················································································· 4 分
x
2 6
3
···································································································· 5 分
AC
2
AB
19.解:原式
4
3
6
··························································································6 分
4
2)(
(
a
a
2)
2
2
a
1
2
a
4
2)(
(
a
a
2)
2(
2)
a
2)(
a
2)
(
a
a
2)(
2
a
2)
(
a
·················································· 2 分
4 2(
(
a
2)
(
a
2)(
a
a
2)
2)
····················································································3 分
1
2a
········································································································· 4 分
当
a
2 2
时
1
1
a
1
2 2 1
1
2 1
2 1
··························································································· 6 分
20.注:每问 2 分
y
A
C
B
P O
C
A
A
C
x
B
P
B
P ,
(3) (2.5 0)
x
x
1
10
是方程的根,且合题意1.2 100 120
21.解:设旅游客车速度为 x Km/h,则小车为1.2x Km/h·········································· 1 分
310
360
·····························································································3 分
1.2
x
x
解方程得 100
···························································································· 7 分
经检验 120
Km/时·····································8 分
答:小车的平均速度为 120Km/时·········································································9 分
22.解:(1)在正方形 ABCD 中, AB BC
BE CF
ABE
△
EAB
CBF
EAB
在 ABO△
··································································································· 1 分
(SAS)··············································································2 分
·························································································· 3 分
90
°··················································································4 分
90
°
AOB
BCF
FBC
ABO
ABO
≌△
°
) 90
°
BCD
ABO
ABC
EAB
180
中,
90
°
,
(
AE BF
···································································································6 分
(2)有 5 对相似三角形···················································································· 7 分
△
△
···························································9 分
∽△
∽△
∽△
∽△
BEO
BFO
△
△
∽△
ABO
ABO
BEO
BCF
AEB
BFC
ABO
ABE
△
23.(1)100··································································································· 2 分
(2)············································································································ 5 分
(3)3000 0.6 1800
该县优秀人数约为 1800 人················································································· 9 分
人数
40
30
20
10
1
1
3
1
24.解:(1) 2
a
40
30
20
5
39.5 49.5 59.5 69.5 79.5 89.5 100
3
3
································································· 2 分
4
分数
2
1
4
3
4
·························································································· 4 分
a
3
1
1
3
4
a
4
1
1 4
1
1
4
1
3
······························································································ 6 分
a
(2) 1
a
2
a
3
a
36
34
4
1
3
12 53
··············································· 9 分
25.解:(1)令二次函数
y
2
ax
bx
,则
c
a
16
4
b c
0
a b c
c
2
0
····························································································1 分
1
2
3
2
a
b
2
c
···································································································· 2 分
过 A B C, , 三点的抛物线的解析式为
y
(2)以 AB 为直径的圆圆心坐标为
O
3 0
,
2
21
x
2
3
2
x
···································4 分
2
O O ····················································································· 5 分
CD
····································································· 6 分
3
2
OC
90
°
90
°
5
2
O C
CD 为圆O 切线
DCO
O CD
O CO
CO O
△
O CO
∽△
3 / 2
2 /
2
OD
CDO
OD
DCO
/
/
CO O
O O OC OC OD
8
3
······················································ 8 分
D 坐标为
80
, ···························································································9 分
3
(3)存在·····································································································10 分
3(
, 或
2
r
r
)
F
3(
r
,
2
r
)
抛物线对称轴为
X
3
2
设满足条件的圆的半径为 r ,则 E 的坐标为
而 E 点在抛物线
y
r
1
2
1
r
1
(
r
2
)
3
2
29
2
3
2
(
21
x
2
3
2
3
2
x
上
2
r
) 2
1
r
2
29
2