2008 年四川省南充市中考数学真题及答案
(满分 100 分,考试时间 90 分钟)
一、细心选一选(本大题共 8 个小题,每小题 3 分,共 24 分)每小题都有代号为 A,B,C,
D 四个答案选项,其中只有一个是正确的,请把正确选项的代号填在相应的括号内.填
写正确记 3 分,不填、填错或填出的代号超过一个记 0 分.
1.计算
( 2)
2
的结果是(
2
)
A. 6
D.6
2.如图,下列选项中不是正六棱柱三视图的是(
C. 2
B. 2
)
A.
B.
C.
(第 2 题图)
D.
3.某地区七、八月份天气较为炎热,小华对其中连续十天每天的最高气温进行统计,依次
得到以下一组数据:34,35,36,34,36,37,37,36,37,37(单位:℃),则这组数
据的中位数和众数分别是(
A.36,37
C.36.5,37
D.37,36.5
B.37,36
)
4.若 1O 的半径为 3cm, 2O 的半径为 4cm,且圆心距 1
O O
2
1cm
,则 1O 与 2O 的位
置关系是(
A.外离
5.已知数据
1
3
)
B.内切
C.相交
D.内含
, 7 , 2.5 , , 5 其中分数出现的频率是(
)
A.20%
B.40%
C.60%
D.80%
6.“5·12”汶川大地震后,世界各国人民为抗震救灾,积极捐款捐物,截止 2008 年 5 月
27 日 12 时,共捐款人民币 327.22 亿元,用科学计数法(保留两位有效数字)表示为(
)
A.
10
3.27 10
B.
10
3.2 10
C.
10
3.3 10
D.
11
3.3 10
7.如图, AB 是 O 直径,
AOC
130
,则 D (
)
A. 65
B. 25
C.15
D.35
D
B
O
A
C
(第 7 题图)
y
O
x
(第 8 题图)
8.二次函数
y
2
ax
bx
的图像如图所示,则点
c
Q a
c
, 在(
b
)
A.第一象限
B.第二象限
C.第三象限
D.第四象限
二、认真填一填(本大题共 4 个小题,每小题 3 分,共 12 分)请将答案直接写在题中横线
上.
9.如图,四边形 ABCD 中, E F G H
, , , 的中点.请你
, , , 分别是边 AB BC CD DA
.
添加一个条件,使四边形 EFGH 为菱形,应添加的条件是
D
H
A
E
B
F
(第 9 题图)
输入 x
G
C
y
y
y
x
2(
x
0)
2
x
2
x
1(0
≤
x
1)
输出 y
2
x
2
x
1(
≥
x
1)
(第 10 题图)
10.根据下面的运算程序,若输入 1
x 时,输出的结果 y
3
.
11.某商场为了解本商场的服务质量,随机调查了本商场的 200 名顾客,调查的结果如图所
示 .根 据图 中 给出 的信 息 ,这 200 名 顾客 中对 该 商场 的服 务 质量 表示 不满 意 的有
人.
A
48%
CD
9%
B
36%
A:满意
B:基本满意
C:说不清
D:不满意
P
(第 11 题图)
A
D
C
O
E B
(第 12 题图)
12.如图,从 O 外一点 P 引 O 的两条切线 PA PB, ,切点分别是 A B, ,若
8cm
,
C 是 AB 上的一个动点(点 C 与 A B, 两点不重合),过点 C 作 O 的切线,分别交
PA PB, 于点 D E, ,则 PED△
的周长是
PA
.
三、(本大题共 2 个小题,每小题 6 分,共 12 分)
13.计算:
11
4
8 1
2
.
14.化简
1
x
1
x
1
x
2
x
,并选择你最喜欢的数代入求值.
四、(本大题共 2 个小题,每小题 6 分,共 12 分)
的对角线相交于点 O ,过点 O 任引直线交 AD 于 E ,交 BC 于 F ,
OF (填“ ”“ ”“ ”),说明理由.
15.如图, ABCD
则OE
A
E
O
D
B
F
(第 15 题图)
C
16.桌面上放有质地均匀、反面相同的 3 张卡片,正面分别标有数字 1,2,3,这些卡片反
面朝上洗匀后放在桌面上,甲从中任意抽出 1 张,记下卡片上的数字后仍反面朝上放回
洗匀,乙再从中任意抽出 1 张,记下卡片上的数字,然后将这两数相加.
(1)请用列表或画树形图的方法求两数和为 4 的概率;
(2)若甲与乙按上述方式做游戏,当两数之和为 4 时,甲胜,反之则乙胜;若甲胜一次
得 6 分,那么乙胜一次得多少分,这个游戏才对双方公平?
五、(本大题共 2 个小题,每小题 8 分,共 16 分)
17.在“5·12”汶川大地震的“抗震救灾”中,某部队接受了抢修映秀到汶川的“213”国
道的任务.需要整修的路段长为 4800m,为了加快抢修进度,获得抢救伤员的时间,该
部队实际工作效率比原计划提高了 20%,结果提前 2 小时完成任务,求原计划每小时抢
修的路线长度.
18.如图,已知 ( 4
, , (2
A
B
n
)
, 是一次函数 y
4)
图像的两个交点.
(1)求反比例函数和一次函数的解析式;
kx b
的图像和反比例函数
my
的
x
y
O
B
A
C
(第 18 题图)
x
(2)求直线 AB 与 x 轴的交点 C 的坐标及三角形 AOB 的面积.
六、(本大题 8 分)
19.如图,已知 O 的直径 AB 垂直于弦CD 于点 E ,过C 点作CG AD∥ 交 AB 的延长线
于点G ,连接CO 并延长交 AD 于点 F ,且CF
(1)试问:CG 是 O 的切线吗?说明理由;
(2)请证明: E 是OB 的中点;
AB ,求CD 的长.
(3)若
8
AD
.
C
A
O
E
B
F
D
G
(第 19 题图)
七、(本大题 8 分)
20.某乒乓球训练馆准备购买 10 副某种品牌的乒乓球拍,每副球拍配 (
x x ≥ 个乒乓球,
3)
已知 A B, 两家超市都有这个品牌的乒乓球拍和乒乓球出售,且每副球拍的标价都为 20
元,每个乒乓球的标价都为 1 元,现两家超市正在促销, A 超市所有商品均打九折(按
原价的 90%付费)销售,而 B 超市买 1 副乒乓球拍送 3 个乒乓球,若仅考虑购买球拍和
乒乓球的费用,请解答下列问题:
(1)如果只在某一家超市购买所需球拍和乒乓球,那么去 A 超市还是 B 超市买更合算?
(2)当 12
x 时,请设计最省钱的购买方案.
八、(本大题 8 分)
21.如图,已知平面直角坐标系中,有一矩形纸片OABC ,O 为坐标原点, AB
x∥ 轴,
( 3 3)
B , ,现将纸片按如图折叠, AD DE, 为折痕,
OAD
30
.折叠后,点O 落
在点 1O ,点 C 落在线段 AB 上的 1C 处,并且 1DO 与 1DC 在同一直线上.
(1)求 1C 的坐标;
(2)求经过三点
O C C, , 的抛物线的解析式;
1
(3)若 P 的半径为 R ,圆心 P 在(2)的抛物线上运动,
P 与两坐标轴都相切时,求 P 半径 R 的值.
B
E
C
y
A
C1
O1
D
x
O
(第 21 题图)
参考答案及评分意见
一、细心选一选(本大题共 8 个小题,每小题 3 分,共 24 分)
1.B; 2.A; 3.A; 4.B; 5. B; 6.C; 7.B; 8.C.
二、认真填一填(本大题共 4 个小题,每小题 3 分,共 12 分)
9. AC BD
或 EG HF
或 EF FG
等(任填一个满足题意的均可);
10. 1
;
3
11.14 ;
12.16cm .
三、(本大题共 2 个小题,每小题 6 分,共 12 分)
13.解:原式
1
2
2
( 2 1)
······································································· 4 分
1
2
2
2
3 2
2
2 1
····························································································5 分
····································································································· 6 分
14.解:原式
x
x
1
1
x
1
(
x x
1)
····································································· 2 分
1
1
x
(
x x
1
1)
···························································································· 4 分
A
D
1
, AD BC∥ ··············································3 分
················································· 4 分
x ············································································································ 5 分
选取除 0 与 1 以外的任何值,求代数式的值·························································· 6 分
注:若选取的值为 0 与 1,该步骤不得分.
四、(本大题共 2 个小题,每小题 6 分,共 12 分)
15.解:填“ ”
理由:四边形 ABCD 是平行四边形
OA OC
2
, 3
在 AOE△
和 COF△
4
2
OA OC
AOE
△
OE OF
16.解:(1)
.·····················································································5 分
··································································································· 6 分
(第 15 题图)
COF
4
中
4 2
F
≌△
3
1
E
3
1
O
C
B
甲:
1
两数之和为
乙:
4)
1
2
1
3
3
9
P
(
P
(2)由(1) (
两数之和为
4)
2
2
3
1
3
2
3
3
1
·······························2 分
·················································································· 4 分
1
3
P
, (
两数之和不为
4)
2
3
x
2
3
6
3
设乙胜一次得 x 分,这个游戏才对双方公平,根据题意得
1
3
x
答:乙胜一次得 3 分,这个游戏才对双方公平.···················································· 6 分
五、(本大题共 2 个小题,每小题 8 分,共 16 分)
17.解:设原计划每小时抢修的路线长为 mx ,根据题意,得
4800
····················································································5 分
2
4800
(1 20 )
%
x
x
解之得
400
x
检验: 400
答:原计划每小时抢修的路线长为 400m.···························································· 8 分
········································································································ 7 分
x
是原方程的解,且符合题的实际意义.
18.解:(1) (2
, 在
4)
B
8
m .
反比例函数的解析式为:
my
上
x
y
.··························· 1 分
8
x
y
O
A
C
x
B
8
x
)
y
n
A
2
上
, 在
点 ( 4
n
A , ····································································································· 2 分
(第 18 题图)
( 4 2)
y
kx b
经过 ( 4 2)
A , , (2
B
, ,
4)
4
2
k b
2
4
k b
解之得
1
k
2
b
一次函数的解析式为:
y
x ··································································· 4 分
2
(2) C 是直线 AB 与 x 轴的交点
当 0
y 时,
x
2
点 ( 2 0)
C , ··································································································5 分
······································································································ 6 分
OC
S
△
2
AOB
S
△
ACO
S
△
BCO
2 4
2 2
1
2
1
2
6 ·············································································································· 8 分
六、(本大题 8 分)
19.(1)解:CG 是 O 的切线········································································· 1 分
理由: CG AD
∥
CFD
180
FCG
AD
CF
CFD
90
.
90
FCG
即OC CG
CG 是 O 的切线.······················································································2 分
(2)第一种方法:
证明:连接 AC ,如图(第 19 题图 1)
AD
且CF AE, 过圆心O
, AE CD
CF
O
A
F
AC AD
AC AD CD
, AC CD
△
ACD
是等边三角形.··········································· 3 分
D
60
C
D
E
B
G
(第 19 题图 1)
·······························································································4 分
点 E 为OB 的中点························································································ 5 分
第二种方法:
证明:连接 BD ,如图(第 19 题图 2)
AB 为 O 的直径
O
A
F
ADB
90
C
D
中,
30
FCD
在 Rt COE△
OE
OC
1
2
1
2
OE
OB
90
AFO
又
AFO
ADB
CF
∥
BDE
△
BD
∽△
OCE
E
B
G
························································································ 3 分
(第 19 题图 2)