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2012年厦门市初中毕业及高中阶段各类学校招生考试
数 学
(试卷满分:150分 考试时间:120分钟)
准考证号 姓名 座位号
注意事项:
1.全卷三大题,26小题,试卷共4页,另有答题卡. 2.答案一律写在答题卡上,否则不能得分. 3.可直接用2B铅笔画图.
一、选择题(本大题有7小题,每小题3分,共21分.每小题都有四个选项,其中有且只有
一个选项正确) 1. -2的相反数是
1
A.2 B.-2 C.±2 D.- 22.下列事件中,是必然事件的是
A. 抛掷1枚硬币,掷得的结果是正面朝上 B. 抛掷1枚硬币,掷得的结果是反面朝上
C. 抛掷1枚硬币,掷得的结果不是正面朝上就是反面朝上
D.抛掷2枚硬币,掷得的结果是1个正面朝上与1个反面朝上
3.图1是一个立体图形的三视图,则这个立体图形是 A.圆锥 B.球
C.圆柱 D.三棱锥
4.某种彩票的中奖机会是1%,下列说法正确的是 A.买1张这种彩票一定不会中奖 B.买1张这种彩票一定会中奖 C.买100张这种彩票一定会中奖
D.当购买彩票的数量很大时,中奖的频率稳定在1%
5.若二次根式x-1有意义,则x的取值范围是 A.x>1 B.x≥1 C.x<1 D.x≤1
6.如图2,在菱形ABCD中,AC、BD是对角线, 若∠BAC=50°,则∠ABC等于 A.40° B.50° C.80° D.100°
7.已知两个变量x和y,它们之间的3组对应值如下表所示.
x y -1 -1 0 1 1 3 正视图俯视图图1A左视图BDC图2则y 与x之间的函数关系式可能是
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A.y=x B.y=2x+1
C.y=x2+x+1
3
D.y= x
二、填空题(本大题有10小题,每小题4分,共40分) 8.计算: 3a-2a= .
9.已知∠A=40°,则∠A的余角的度数是 . 10.计算: m3÷m2= .
11.在分别写有整数1到10的10张卡片中,随机抽取1张
卡片,则该卡片上的数字恰好是奇数的概率是 . 12.如图3,在等腰梯形ABCD中,AD∥BC,对角线AC
与BD相交于点O,若OB=3,则OC= . 13.“x与y的和大于1”用不等式表示为 . 14.如图4,点D是等边△ABC内一点,如果△ABD绕点A
逆时针旋转后能与△ACE重合,那么旋转了 度. 15.五边形的内角和的度数是 .
16.已知a+b=2,ab=-1,则3a+ab+3b= ;
a2+b2= .
πr
17.如图5,已知∠ABC=90°,AB=πr,BC=,半径为r
2
的⊙O从点A出发,沿A→B→C方向滚动到点C时停止. 请你根据题意,在图5上画出圆心..O运动路径的示意图; 圆心O运动的路程是 . 三、解答题(本大题有9小题,共89分) 18.(本题满分18分)
(1)计算:4÷(-2)+(-1)2×40; (2)画出函数y=-x+1的图象;
(3)已知:如图6,点B、F、C、E在一条直线上,
∠A=∠D,AC=DF,且AC∥DF. 求证:△ABC≌△DEF.
AOBD图3CAEDB图4COA→B图5CABCF图6DE?3x+y=4,19.(本题满分7分)解方程组: ?
?2x-y=1.
20.(本题满分7分)已知:如图7,在△ABC中,∠C=90°,点D、E分别在边AB、AC
上,DE∥BC,DE=3, BC=9. AD
(1)求 的值;
AB
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(2)若BD=10,求sin∠A的值.
21.(本题满分7分)已知A组数据如下:
0,1,-2,-1,0,-1,3.
(1)求A组数据的平均数;
(2)从A组数据中选取5个数据,记这5个数据为B组数据. 要求B组数据满足两
个条件:①它的平均数与A组数据的平均数相等;②它的方差比A组数据的方差大.你选取的B组数据是 ,请说明理由. 【注:A组数据的方差的计算式是
1
SA2=[(x1-—x)2+(x2-—x)2+(x3-—x)2+(x4-—x)2+(x5-—x)2+(x6-—x)2+(x7-—x)2]】
7
22.(本题满分9分)工厂加工某种零件,经测试,单独加工完成这种零件,甲车床需用
x小时,乙车床需用 (x2-1)小时,丙车床需用(2x-2)小时.
2
(1)单独加工完成这种零件,若甲车床所用的时间是丙车床的 ,求乙车床单独加工
3
完成这种零件所需的时间;
(2)加工这种零件,乙车床的工作效率与丙车床的工作效率能否相同?请说明理由.
23.(本题满分9分)已知:如图8,⊙O是△ABC的外接圆,AB为⊙O的直径,弦CD
交AB于E,∠BCD=∠BAC . (1)求证:AC=AD;
(2)过点C作直线CF,交AB的延长线于点F,
若∠BCF=30°,则结论“CF一定是⊙O的切线” 是否正确?若正确,请证明;若不正确,请举反例.
CFBDEOA图824.(本题满分10分)如图9,在平面直角坐标系中,已知点A(2,3)、B(6,3),连结AB.
如果点P在直线y=x-1上,且点P到直线AB的距离小于1,那么称点P是线段AB的“邻近点”.
75
(1)判断点C( , ) 是否是线段AB的“邻近点”,并说明理由;
22
(2)若点Q (m,n)是线段AB的“邻近点”,求m的取值范围.
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25.(本题满分10分)已知□ABCD,对角线AC与BD相交于点O,点P在边AD上,过
点P分别作PE⊥AC、PF⊥BD,垂足分别为E、F,PE=PF. (1)如图10,若PE=3,EO=1,求∠EPF的度数; (2)若点P是AD的中点,点F是DO的中点,
BF =BC+32-4,求BC的长.
AEOPFCDB图10k226.(本题满分12分)已知点A(1,c)和点B (3,d )是直线y=k1x+b与双曲线y=(k2
x
>0)的交点.
(1)过点A作AM⊥x轴,垂足为M,连结BM.若AM=BM,求点B的坐标; k2 (2)设点P在线段AB上,过点P作PE⊥x轴,垂足为E,并交双曲线y=(k2>0)
x
于点N.当
PN1
取最大值时,若PN= ,求此时双曲线的解析式. NE2
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2012年厦门市初中毕业及高中阶段各类学校招生考试
数学参考答案及评分标准
说明:
1.解答只列出试题的一种或几种解法.如果考生的解法与所列解法不同,可参照解答中评分标准相应评分;
2.评阅试卷,要坚持每题评阅到底,不能因考生解答中出现错误而中断对本题的评阅.如果考生的解答在某一步出现错误,影响后续部分而未改变本题的内容和难度,视影响的程度决定后继部分的给分,但原则上不超过后续部分应得分数的一半; 3.解答题评分时,给分或扣分均以1分为基本单位.
一、选择题(本大题共7小题,每小题3分,共21分)
题号 选项 1 A 2 C 3 A 4 D 5 B 6 C 7 B 二、填空题(本大题共10小题,每题4分,共40分)
1
8. a. 9. 50°. 10. m. 11. . 12. 3. 13. x+y>1.
215. 540°. 16. 5; 6. 17. ;2πr.
14. 60.
三、解答题(本大题共9小题,共89分) 18.(本题满分18分)
(1)解:4÷(-2) +(-1)2×40
=-2+1×1 ··································································· 4分 =-2+1 ········································································ 5分 =-1. ·········································································· 6分
(2)解:正确画出坐标系 ······························································· 8分
正确写出两点坐标 ·························································· 10分 画出直线 ······································································ 12分
(3)证明:∵ AC∥DF, ……13分
∴ ∠ACB=∠DFE. ……15分 又∵ ∠A=∠D, ……16分 AC=DF, ……17分 ∴ △ABC≌△EDF. ……18分
19.(本题满分7分)
ABCFDE?3x+y=4, ①解1:?
?2x-y=1. ②
①+②,得 ····································································· 1分 5x=5, ·········································································· 2分 x=1. ··········································································· 4分
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将x=1代入 ①,得 3+y=4, ······································································· 5分 y=1. ··········································································· 6分
?x=1,∴? ······································································ 7分 ?y=1.
解2:由①得 y=4-3x. ③ ········································ 1分 将③代入②,得 2x-(4-3x) =1. ···························································· 2分 得x=1. ······································································· 4分 将x=1代入③ ,得 y=4-3×1 ····································································· 5分 =1. ··········································································· 6分
?x=1,∴? ······································································ 7分 ?y=1.
20.(本题满分7分)
(1)解:∵ DE∥BC ,∴ △ADE∽△ABC. ……1分
ADDE
∴ = . ……2分
ABBC
AD1
∴ =.
AB3
(2)解1:∵
∴
AD1
=,BD=10, AB3
……3分
AEDCGBAD1
= ······························································· 4分
AD+103
∴ AD=5 ····································································· 5分 经检验,符合题意. ∴ AB=15. 在Rt△ABC中, ······························································ 6分 BC3
sin∠A==. ····························································· 7分
AB5
解2: ∵
∴
AD1
=,BD=10, AB3
AD1
= ······························································· 4分
AD+103
∴ AD=5 ····································································· 5分 经检验,符合题意. ∵ DE∥BC,∠C=90° ∴ ∠AED=90° 在Rt△AED中, ······························································ 6分 ED3sin∠A==. ····························································· 7分
AD5
解3:过点D作DG⊥BC,垂足为G. ∴ DG∥AC.
∴∠A=∠BDG. ····························································· 4分
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又∵ DE∥BC,∴四边形ECGD是平行四边形. ∴ DE=CG. ··································································· 5分 ∴ BG=6.
在Rt△DGB中, ····························································· 6分 BD3∴ sin∠BDG==. ···················································· 7分
GB53
∴ sin∠A=.
5
21.(本题满分7分)
0+1-2-1+0-1+3
(1)解:A组数据的平均数是 ··························· 1分
7=0. ················································· 3分
(2)解1:选取的B组数据:0,-2,0,-1,3. ····························· 4分
∵ B组数据的平均数是0. ··············································· 5分 ∴ B组数据的平均数与A组数据的平均数相同.
∴ SB2=
1416 ,SA2= . ··················································· 6分 57
1416
∴ >. ··································································· 7分
57
∴ B组数据:0,-2,0,-1,3.
解2:B组数据:1,-2,-1,-1,3. ··································· 4分
∵ B组数据的平均数是0. ··············································· 5分 ∴ B组数据的平均数与A组数据的平均数相同.
∵SA2=∴
1616, SB2= . ···················································6分 75
1616> ······································································ 7分 57
∴ B组数据:1,-2,-1,-1,3.
22.(本题满分9分) (1)解:由题意得,
2
x=(2x-2) ··································································· 1分 3∴ x=4. ······································································· 2分 ∴ x2-1=16-1=15(小时). ············································· 3分 答:乙车床单独加工完成这种零件所需的时间是15小时. ······· 4分
(2)解1:不相同. ······································································ 5分
若乙车床的工作效率与丙车床的工作效率相同,由题意得, ······ 6分
11
= . ······························································ 7分 x2-12x-211∴ =. x+12
∴ x=1. ····································································· 8分 经检验,x=1不是原方程的解. ∴ 原方程无解. ··················· 9分 答:乙车床的工作效率与丙车床的工作效率不相同.
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解2:不相同. ······································································ 5分
若乙车床的工作效率与丙车床的工作效率相同,由题意得, ······ 6分 x2-1=2x-2. ································································ 7分 解得,x=1. ·································································· 8分 此时乙车床的工作时间为0小时,不合题意. ························ 9分 答:乙车床的工作效率与丙车床的工作效率不相同.
23.(本题满分9分)
(1)证明1:∵∠BCD=∠BAC,
︵︵
∴ BC=BD .
……1分
CG∵ AB为⊙O的直径, ∴ AB⊥CD, ……2分 CE=DE. ……3分 ∴ AC=AD . ……4分
证明2:∵∠BCD=∠BAC,
FBDEOA︵︵
∴ BC=BD . ····························································· 1分 ︵︵
∵ AB为⊙O的直径, ∴ BCA=BDA . ··························· 2分 ︵︵
∴ CA=DA . ································································ 3分
∴ AC=AD . ································································ 4分
证明3:∵ AB为⊙O的直径,∴ ∠BCA=90°. ······················· 1分
∴ ∠BCD+∠DCA=90°, ∠BAC+∠CBA=90° ∵∠BCD=∠BAC,∴∠DCA=∠CBA ································ 2分
︵︵
∴ CA=DA . ································································ 3分
∴ AC=AD . ································································ 4分
(2)解1:不正确. ······································································ 5分
连结OC.
当 ∠CAB=20°时, ························································ 6分 ∵ OC=OA,有 ∠OCA=20°.
∵ ∠ACB=90°, ∴ ∠OCB=70°. ··························· 7分 又∵∠BCF=30°, ∴∠FCO=100°, ·························································· 8分 ∴ CO与FC不垂直. ······················································ 9分 ∴ 此时CF不是⊙O的切线.
解2:不正确. ······································································ 5分
连结OC.
当 ∠CAB=20°时, ························································ 6分 ∵ OC=OA,有 ∠OCA=20°.
∵ ∠ACB=90°, ∴ ∠OCB=70°. ··························· 7分 又∵∠BCF=30°, ∴∠FCO=100°, ·························································· 8分
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