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2009年广西梧州市中考数学真题及答案.doc

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2009 年广西梧州市中考数学真题及答案 说明:1.本试卷共 8 页(试题卷 4 页,答题卷 4 页),满分 120 分,考试时间 120 分钟. 2.答卷前,将准考证号、姓名写在答题卷密封线内,答案请写在答题卷相应的 区域内,在试题卷上答题无效 .......... 一、填空题(本大题共 10 小题,每小题 3 分,共 30 分.) 1.6 的相反数是 ★ . A 2.比较大小:-3 ★ -4.(用“>”“=”或“<”表示) 3.一组数据为 1,2,3,4,5,6,则这组数据的中位数是 ★ . 4.因式分解: 2 2 x 18 = ★ . D B C 图(1) 5.如图(1),△ABC中,∠A=60°,∠C=40°,延长 CB到 D ,则∠ABD= ★ 度. 6.将点 A(1,-3)向右平移 2 个单位,再向下平移 2 个单位后得到点 B(a,b),则 ab= ★ . 7.某蔬菜基地的圆弧形蔬菜大棚的剖面如图(2)所示,已知 AB=16m,半径 OA=10m,则中间柱 CD的高度为 ★ m. 8.在△ABC中,∠C=90°, BC=6 cm, sin A 3 5 , A 则 AB的长是 ★ cm. C D B O 图(2) 9 . 一 个 扇 形 所 在 圆 的 半 径 为 3 c m , 扇 形 的 圆 心 角 为 1 2 0 ° , 则 扇 形 的 面 积 是 ★ cm2. (结果保留 π ) 10.图(3)是用火柴棍摆成的边长分别是 1,2,3 根火柴棍时的正方形.当边长为 n根火柴棍时,设摆出 的正方形所用的火柴棍的根数为 s ,则 s = ★ . (用 n的代数式表示 s ) …… n=1 n=2 n=3 图(3) 二、选择题(本大题共 8 小题,每小题 3 分,共 24 分.在每小题给出的四个选项中, 只有一项是正确的,每小题选对得 3 分,选错、不选或多选均得零分.) 11.在函数 y  1  x 2 中,自变量 x的取值范围是( ) A. 2x B. 2x C. x ≤ 2 D. x ≥ 2 12.下列运算正确的是( )
A. C. 2 a (   a 3 a 32) 6 a   6 a 4 B. D. a a 2 2 a   3 a a a 13.一个布袋中有 4 个除颜色外其余都相同的小球,其中 3 个白球,1 个红球.从袋中任意摸出 1 个球是白 球的概率是( ) A. 3 4 14.不等式组 B. 1 4 C. 2 3 D. 1 3 2    ≥ 2 0   1  x x 的解集在数轴上表示为( ) -2 -1 0 1 2 3 -2 -1 0 1 2 3 -2 -1 0 1 2 3 -2 -1 0 1 2 3 A. B. C. D. 15.在下列对称图形中,对称轴的条数最少的图形是( ) A.圆 B.等边三角形 C.正方形 (D)正六边形 16.在一个仓库里堆放有若干个相同的正方体货箱,仓库管理员将这堆货箱的三视图画出来,如图(4), 则这堆货箱共有( ) 图(4) A.6 个 主视图 B.5 个 左视图 俯视图 C.4 个 D.3 个 x 1 7 . 已 知 点 A( 1 y, ) 、 B( 2 x 1 y, ) 是 反 比 例 函 数 2 y  ( k x 0k ) 图 象 上 的 两 点 , 若 A. x 1 y 1   0 0 x 2 y 2 ,则有( B. y 2 ) 0  y 1 C. y 1  y 2  0 18.如图(5),正方形ABCD中,E为AB的中点,AF⊥DE于点O, 则 A. C. 52 3 2 3 B. 1 3 D. 1 2 三、解答题(本大题共 8 小题,满分 66 分.) 19.(本题满分 6 分)计算: 12   11   2      2sin 60  20.(本题满分 6 分)解方程: ( x  2 )3  (2 xx  )3  0 y 2  y 1  0 等于( ) D. AO DO D A C F O E B 图(5) 21.(本题满分 6 分) 为了解全市太阳能热水器的销售情况,某调查公司对人口为 100 万人的某县进行调查,对调查所得的 数据整理后绘制成如图(6)所示的统计图.请据图解答下列问题:
中档 · 高档占 10% 低档占 30% 图(6)-1 2008 年该县销售高、中、低 档太阳能热水器的数量统计图 图(6) 台 1000 700 600 600 700 1000 图(6)-2 2005 2006 2007 2008 2005-2008 年该县销售太 阳能热水器的数量统计图 年 (1)2008 年该县销售中档..太阳能热水器 ★ 台. (2)若 2007 年销售太阳能热水器的台数是 2005 年的 1.5 倍,请补全图(6)-2 的条形图. (3)若该县所在市的总人口约为 500 万人,估计 2008 年全市销售多少台高档太阳能热水器. 22.(本题满分 8 分) 某工厂要招聘甲、乙两种工种的工人 150 人,甲、乙两种工种的工人的月工资分别为 600 元和 1000 元. (1)设招聘甲种工种工人 x人,工厂付给甲、乙两种工种的工人工资共 y元,写出 y(元)与 x(人)的 函数关系式; (2)现要求招聘的乙种工种的人数不少于甲种工种人数的 2 倍,问甲、乙两种工种 各招聘多少人时,可使得每月所付的工资最少? 23.(本题满分 8 分) 如图(7),△ABC中,AC的垂直平分线 MN交 AB于 点 D,交 AC于点 O,CE∥AB交 MN于 E,连结 AE、CD. D M (1)求证:AD=CE; (2)填空:四边形 ADCE的形状是 ★ . A O E N B C 图(7) 24.(本题满分 10 分)
由甲、乙两个工程队承包某校校园绿化工程,甲、乙两队单独完成这项工程所需时间比是 3︰2,两队 合做 6 天可以完成. (1)求两队单独完成此项工程各需多少天? (2)此项工程由甲、乙两队合做 6 天完成任务后,学校付给他们 20000 元报酬,若 按各自完成的工程量分配这笔钱,问甲、乙两队各得到多少元? 25.(本题满分 10 分) 如图(8)所示,△ABC内接于⊙O,AB是⊙O的直径,点 D在⊙O 上,过点 C的切线交 AD的延长线于 点 E,且 AE⊥CE,连接 CD. (1)求证:DC=BC; (2)若 AB=5,AC=4,求 tan∠DCE的值. E D A C B · O 图(8) 26.(本题满分 12 分) 如图(9)-1,抛物线 y  ax 交于另一点 B. (1)求此抛物线的解析式; 2 3  ax b  经过 A( 1 ,0),C(3, 2 )两点,与 y 轴交于点 D,与 x 轴 (2)若直线 y  kx  (1  k )0 将四边形 ABCD面积二等分,求 k 的值; (3)如图(9)-2,过点 E(1,1)作 EF⊥ x 轴于点 F,将△AEF绕平面内某点旋转 180°得△MNQ(点 M、N、 Q分别与点 A、E、F对应),使点 M、N在抛物线上,作 MG⊥ x 轴于点 G,若线段 MG︰AG=1︰2,求点 M,N 的坐标. y A O D 图(9)-1 B x A O C y=kx+1 y E F Q B x G M N 图(9)-2
一、填空题(本大题共 10 小题,每小题 3 分,共 30 分.) 2009 年梧州市初中毕业升学考试 数学参考答案及评分标准 题号 答案 题号 答案 1 6 题号 6 答案 15 2 > 7 4 12 C 11 B 3 3.5 13 8 A 10 三、解答题(本大题共 8 小题,满分 66 分.) 4 2(x+3)(x-3) 15 14 16 5 100 17 D 9 B 3 π C 10 2 ( n n  A 1) 18 二、选择题(本大 题 共 8 小 题 , 每 小 题 3 分,共 D 24 分.) 2 3 = 32  22 20.解: 19.解:原式= ······································································ 3 分 3 2 32  ··········································································4 分 3  ···················································································· 6 分 2 = )23 ( )(3 x x x    ········································································ 2 分 0 )3 ( 3)(3 x x    ··············································································3 分 03 x 03 3 x ········································································· 4 分 或 1 3 2 x ··············································································· 6 分 即 ·················································································· 2 分 (2)在右图上补全条形图如图. ······································································4 分 21.解:(1) 600 1 x 或 0 台 700 600 1000 700 600 1000 900 2005 2006 2007 2008 年 图(6)-2 ) x x y   22.解:(1) y 600  400  (2)依题意得,150 ·····································································6 分 (3)500÷100×1000×10%=500 1000 150( x  ···························································· 2 分 150000 ··································································3 分 2 x  ≥ ································································ 5 分 ··············································································6 分 因为-400<0,由一次函数的性质知,当 x=50 时,y有最小值··················· 7 分 所以 150-50=100 x ≤ 50 x 答: 甲工种招聘 50 人,乙工种招聘 100 人时可使得每月所付的工资最少. (8 分) A 23.(1)证明:∵MN是 AC的垂直平分线························· 1 分 D M O E N
∴OA=OC ∠AOD=∠EOC=90°··················· 3 分 ∵CE∥AB ∴∠DAO=∠ECO ··································· 4 分 ∴△ADO≌△CEO ····································· 5 分 ∴AD=CE ··········································· 6 分 (2)四边形 ADCE是菱形. ·····································8 分 (填写平行四边形给 1 分) 24.解:(1)设甲队单独完成此项工程需 x天,由题意得······································ 1 分  1 ······················································································ 3 分 6 x  6 2 x 3 解之得 15x 经检验, 15x 所以甲队单独完成此项工程需 15 天, ························································································ 4 分 是原方程的解. ······························································5 分 乙队单独完成此项工程需 15× 2 3 =10(天)················································· 6 分 (2)甲队所得报酬: 20000  1 15  6 8000 (元)············································8 分 乙队所得报酬: 20000  1 10  6 12000 (元)···················································· 10 分 25.(1)证明:连接 OC··················································································· 1 分 ∵OA=OC ∴∠OAC=∠OCA ∵CE是⊙O的切线 ∴∠OCE=90° ········································· 2 分 ∵AE⊥CE C E D B ∴∠AEC=∠OCE=90° ∴OC∥AE ················································3 分 ∴∠OCA=∠CAD ∴∠CAD=∠BAC ········································4 分 ∴  DC BC ∴DC=BC ····························································································· 5 分 (2)∵AB是⊙O的直径 ∴∠ACB=90° 图(8) · O A  2  2  2 5  2 4  ∴ AB BC AC ···················································6 分 3 ∵∠CAE=∠BAC ∠AEC=∠ACB=90° ∴△ACE∽△ABC·················································································· 7 分 EC  BC AC AB ∴
∴ EC 3 4 5 ∵DC=BC=3 12EC 5 ········································································ 8 分 ∴ ED  2 DC  CE 2  2 3  12( 5 2 )  9 5 ·················································· 9 分 ∴ tan  DCE  ED EC  9 5 12 5  3 4 ······························································ 10 分 26.(1)解:把 A( 1 ,0),C(3, 2 )代入抛物线 y  ax 2 3  ax b  得  )1(    2 a 9 a )1(3  9 ba   ba  2 0 ······································································ 1 分 整理得 0 4   b  ba  2  ……………… 2 分 解得 a     b  1 2 2  ………………3 分 1 2 x 2 0  3 2 x  2 ·························································· 4 分 x 解得 1   1 , x 2 4 ∴AB∥CD ∴四边形 ABCD是梯形. 8 ··························· 5 分 y 与 x轴的交点为 H, 3 , 2 )················6 分 k 将四边形 ABCD面积二等分 ∴抛物线的解析式为 y  (2)令 1 2 x 2  x 3 2  2 ∴ B点坐标为(4,0) 又∵D点坐标为(0, 2 ) 1 2 kx   2)35( )0  (1  ∴S 梯形 ABCD = y  设直线 k 与 CD的交点为 T, 则 H( ∵直线 ∴S 梯形 AHTD = S 梯形 ABCD=4 1 ,0), T( k )0 y  (1   k kx 1 2 1 2)311(   2 k 4k 3 k ∴ ∴ H O A B x D T C y=kx+1 图(9) -1 y E F Q A O B x G M N 图(9) -2 4 ································ 7 分 ···················································· 8 分 (3)∵MG⊥ x 轴于点 G,线段 MG︰AG=1︰2  m 1 2 ∴设 M(m, ),··································· 9 分 ∵点 M在抛物线上 m ∴  1   2 1 2 2 m  m  2 3 2  3 , m 解得 1 ∴M点坐标为(3, 2 )··········································································· 11 分 (舍去) ························ 10 分   m 2 1
根据中心对称图形性质知,MQ∥AF,MQ=AF,NQ=EF, ∴N点坐标为(1, 3 ) ········································································· 12 分
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