2008年陕西省初中毕业学业考试
数 学
第Ⅰ卷(选择题 共30分)
A卷
一、选择题(共10小题,每小题3分,计30分.每小题只有一个选项是符合题意的)
1.零上13℃记作 13℃,零下2℃可记作( )
A.2 B. C.2℃ D. 2℃
2.如图,这个几何体的主视图是( )
(第2题图) |
A. B. C. D. |
3.一个三角形三个内角的度数之比为 ,这个三角形一定是( )
A.直角三角形 B.等腰三角形
C.锐角三角形 D.钝角三角形
A. B. |
C. D. |
5.在“爱的奉献”抗震救灾大型募捐活动中,文艺工作者积极向灾区捐款.其中8位工作者的捐款分别是5万,10万,10万,10万,20万,20万,50万,100万.这组数据的众数和中位数分别是( )
A.20万,15万 B.10万,20万 C.10万,15万 D.20万,10万
(第6题图) |
O |
A |
D |
C |
B |
需要添加的条件是( )
A. B.
C. D.
7.方程 的解是( )
A. B.
(第8题图) |
3 |
y |
x |
B |
A |
2 |
8.如图,直线 对应的函数表达式是( )
A. B.
C. D.
9.如图,直线 与半径为2的 相切于点 是 上
O |
(第9题图) |
D |
F |
E |
A |
C |
B |
A.2 B. C. D.
10.已知二次函数 (其中 ),
关于这个二次函数的图象有如下说法:
①图象的开口一定向上;
②图象的顶点一定在第四象限;
③图象与 轴的交点至少有一个在 轴的右侧.
以上说法正确的个数为( )
A.0 B.1 C.2 D.3
B卷
第Ⅱ卷(非选择题 共90分)
二、填空题(共6小题,每小题3分,计18分)
11.若 ,则 的余角的大小是 .
12.计算: .
(第14题图) |
O |
(B) |
A |
D |
x |
y |
C |
式是 .
14.如图,菱形 的边长为2, ,
则点 的坐标为 .
15.搭建如图①的单顶帐篷需要17根钢管,这样的帐篷按图②,
图③的方式串起来搭建,则串7顶这样的帐篷需要 根钢管.
图1 图2 图3
|
(第15题图) |
|
|
|
A |
B |
D |
C |
(第16题图) |
16.如图,梯形 中, ,
,且 ,分别以
为边向梯形外作正方形,其面积分别为 ,则 之间的关系
是 .
三、解答题(共9小题,计72分.解答应写出过程)
17.(本题满分6分)
先化简,再求值:
,其中 , .
18.(本题满分6分)
已知:如图, 三点在同一条直线上, , , .
A |
D |
B |
C |
E |
(第18题图) |
19.(本题满分7分)
下面图①,图②是某校调查部分学生是否知道母亲生日情况的扇形和条形统计图:
不知道
|
记不清 |
|
|
图① |
学生数/名 |
50 |
40 |
30 |
20 |
10 |
选项 |
图② |
(第19题图) |
知道
|
根据上图信息,解答下列问题:
(1)求本次被调查学生的人数,并补全条形统计图;
(2)若全校共有2700名学生,你估计这所学校有多少名学生知道母亲的生日?
(3)通过对以上数据的分析,你有何感想?(用一句话回答)
20.(本题满分7分)
阳光明媚的一天,数学兴趣小组的同学们去测量一棵树的高度(这棵树底部可以到达,顶部不易到达),他们带了以下测量工具:皮尺、标杆、一副三角尺、小平面镜.请你在他们提供的测量工具中选出所需工具,设计一种测量方案.
(1)所需的测量工具是: ;
(2)请在下图中画出测量示意图;
(3)设树高 的长度为 ,请用所测数据(用小写字母表示)求出 .
第20题图 |
21.(本题满分8分)
如图,桌面上放置了红、黄、蓝三个不同颜色的杯子,杯口朝上.我们做蒙眼睛翻杯子(杯口朝上的翻为杯口朝下,杯口朝下的翻为杯口朝上)的游戏.
(1)随机翻一个杯子,求翻到黄色杯子的概率;
(2)随机翻一个杯子,接着从这三个杯子中再随机翻一个,请利用树状图求出此时恰好有一个杯口朝上的概率.
红 |
黄 |
蓝 |
(第21题图) |
22.(本题满分8分)
项目 |
| 单价(元/棵) | 成活率 | 劳务费(元/棵) | |
A | 15 | 3 | ||
B | 20 | 4 |
设购买 种树苗 棵,造这片林的总费用为 元.解答下列问题:
(1)写出 (元)与 (棵)之间的函数关系式;
(2)假设这批树苗种植后成活1960棵,则造这片林的总费用需多少元?
23.(本题满分8分)
如图,在 中, , , , 是 的角平分线.过 三点的圆与斜边 交于点 ,连接 .
A |
C |
D |
E |
B |
(第23题图) |
(2)求 外接圆的半径.
24.(本题满分10分)
如图,矩形 的长、宽分别为 和1,且 ,点 ,连接 .
(1)求经过 三点的抛物线的表达式;
(2)若以原点为位似中心,将五边形 放大,使放大后的五边形的边长是原五边形对应边长的3倍.请在下图网格中画出放大后的五边形 ;
1 |
O |
x |
y |
2 |
3 |
4 |
5 |
6 |
7 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
|
|
A |
B |
C |
D |
E |
(第24题图) |
25.(本题满分12分)
某县社会主义新农村建设办公室,为了解决该县甲、乙两村和一所中学长期存在的饮水困难问题,想在这三个地方的其中一处建一所供水站.由供水站直接铺设管道到另外两处.
如图,甲,乙两村坐落在夹角为 的两条公路的 段和 段(村子和公路的宽均不计),点 表示这所中学.点 在点 的北偏西 的3km处,点 在点 的正西方向,点 在点 的南偏西 的 km处.
为使供水站铺设到另两处的管道长度之和最短,现有如下三种方案:
方案一:供水站建在点 处,请你求出铺设到甲村某处和乙村某处的管道长度之和的最小值;
方案二:供水站建在乙村(线段 某处),甲村要求管道建设到 处,请你在图①中,画出铺设到点 和点 处的管道长度之和最小的线路图,并求其最小值;
方案三:供水站建在甲村(线段 某处),请你在图②中,画出铺设到乙村某处和点 处的管道长度之和最小的线路图,并求其最小值.
综上,你认为把供水站建在何处,所需铺设的管道最短?
M |
A |
E |
C |
D |
B |
F |
|
乙村 |
甲村 |
东 |
北 |
图① |
M |
A |
E |
C |
D |
B |
F |
|
乙村 |
甲村 |
图② |
(第25题图) |
O |
O |
2008年陕西省初中毕业学业考试
数学参考答案(A卷)
一、选择题
1.D 2.A 3.D 4.C 5.C
6.D 7.A 8.A 9.B 10.C
二、填空题
11. 12. 13. 14.
15.83 16.
三、解答题
17.解:原式 ···································································· (1分)
················································································· (2分)
···································································································· (3分)
················································································································· (4分)
当 , 时,原式 ······························································ (6分)
18.证明: ,
, .········································································ (2分)
又 ,
.······································································································· (4分)
又 ,
.··························································································· (6分)
19.解:(1) (名),
本次调查了90名学生.······················································································ (2分)
补全的条形统计图如下:
学生数/名 |
50 |
40 |
30 |
20 |
10 |
选项 |
(第19题答案图) |
······························································································································ (4分)
(2) (名),
估计这所学校有1500名学生知道母亲的生日.··················································· (6分)
(3)略(语言表述积极进取,健康向上即可得分).·············································· (7分)
20.解:(1)皮尺、标杆.···················································································· (1分)
(2)测量示意图如右图所示.··············································································· (3分)
(3)如图,测得标杆 ,树和标杆的影长分别为 , .········· (5分)
C |
D |
E |
F |
B |
A |
(第20题答案图) |
.
.
.················· (7分)
※注:其它符合题意的正确解答参照以上解题过程赋分.
21.解:(1) (翻到黄色杯子) .······························································· (3分)
(2)将杯口朝上用“上”表示,杯口朝下用“下”表示,画树状图如下:
开始(上,上,上) |
(上,上,上) |
(上,下,下) |
(下,上,下) |
(上,上,下) |
(上,下,下) |
(上,上,上) |
(下,下,上) |
(上,下,上) |
(下,上,下) |
(下,下,上) |
(上,上,上) |
(下,上,上) |
(第21题答案图) |
由上面树状图可知:所有等可能出现的结果共有9种,其中恰好有一个杯口朝上的有6种,
······························································································································ (7分)
(恰好有一个杯口朝上) .······································································ (8分)
22.解:(1) ·························· (3分)
(2)由题意,可得: .
.·········································································································· (5分)
当 时, .
造这片林的总费用需45 000元.········································································· (8分)
23.(1)证明: , 为直径.·················································· (1分)
又 是 的角平分线,
, .
.······································································································· (3分)
(2)解: ,
.
, .
为直径, .
, .··································································· (6分)
. .
.
外接圆的半径为 .········································································ (8分)
24.解:(1)设经过 三点的抛物线的表达式为 .
.······································································· (1分)
,解之,得 .
过 三点的抛物线的表达式为 .······························· (4分)
(2)
(第24题答案图)
······························································································································ (7分)
(3)不能.理由如下:························································································· (8分)
设经过 三点的抛物线的表达式为 .
,
,解之,得 .
, , .
经过 三点的抛物线不能由(1)中抛物线平移得到.······················· (10分)
25.解:方案一:由题意可得: ,
点 到甲村的最短距离为 .······································································· (1分)
点 到乙村的最短距离为 .
将供水站建在点 处时,管道沿 铁路建设的长度之和最小.
即最小值为 .········································································ (3分)
方案二:如图①,作点 关于射线 的对称点 ,则 ,连接 交 于点 ,则 .
, .·········································································· (4分)
在 中,
, ,
, 两点重合.即 过 点.············································· (6分)
在线段 上任取一点 ,连接 ,则 .
,
把供水站建在乙村的 点处,管道沿 线路铺设的长度之和最小.
M |
A |
E |
C |
D |
B |
F |
|
|
甲村 |
东 |
北 |
M |
A |
E |
C |
D |
B |
F |
|
(第25题答案图①) |
A |
G |
|
|
H |
(第25题答案图②) |
P |
O |
O |
|
N |
方案三:作点 关于射线 的对称点 ,连接 ,则 .
作 于点 ,交 于点 ,交 于点 ,
为点 到 的最短距离,即 .
在 中, , ,
. .
, 两点重合,即 过 点.
在 中, , .············································· (10分)
在线段 上任取一点 ,过 作 于点 ,连接 .
显然 .
把供水站建在甲村的 处,管道沿 线路铺设的长度之和最小.
即最小值为 .································································ (11分)
综上, , 供水站建在 处,所需铺设的管道长度最短.········ (12分)