2008年呼和浩特市中考数学试题 2

  • 格式:doc
  • 大小:945.60 KB
  • 文档页数:11

2008年呼和浩特市中考试卷数 学注意事项:本试卷满分120分.考试时间120分钟.一、选择题(本题包括10个小题,每题3分,共30分.在每小题给出的四个选项中,只有一项符合题意,请把该选项的序号填入题后面的括号内) 1.3-的倒数是( ) A .3B .13C .13-D .3-2.下列运算中,结果正确的是( ) A .336x x x = B .224325x x x += C .235()x x =D .222()x y x y +=+3.据CCTV —1报道,截止到6月13日社会各界向汶川地震灾区捐款达455.02亿元.写成科学计数法是( ) A .84.550210⨯元 B .94.550210⨯元 C .104.550210⨯元D .114.550210⨯元4.如图,AB DE ∥,65E ∠=,则B C ∠+∠=( ) A .135B .115C .36D .655.同时抛掷两枚均匀硬币,正面都同时向上的概率是( ) A .13B .14C .12D .346.如图,矩形ABCD 内接于O,且AB =1BC =.则图中阴影部分所表示的扇形AOD 的面积为( )A .3πB .4πC .6πD .8π7.下列说法正确的是( )A .抽样调查选取样本时,所选样本可按自己的爱好抽取B .某工厂质检员测某批灯泡的使用寿命采用普查法C .想准确了解某班学生某次测验成绩,采用抽样调查,但需抽取的样本容量较大D .检测某城市的空气质量,采用抽样调查 8.图(1),(2),(3),(4)四个几何体的三视图为以下四组平面图形,其中与图(3)对应的三视图是( )B EDA CF(1) (2) (3)9.已知二次函数2(0)y ax bx c a =++≠的图象如图(1)所示,则直线y ax b =+与反比例函数acy x=,在同一坐标系内的大致图象为( )10.如图,已知梯形ABCD ,AD BC ∥,4AD DC ==,8BC =,点N 在BC 上,2CN =,E 是AB 中点,在AC 上找一点M 使EM MN +的值最小,此时其最小值一定等于( )A .6B .8C .4 D.二、填空题(本题包括6个小题,每题3分,共18分.本题要求把正确结果填在每题横线上,不需要解答过程)11.计算:222233y x y x-÷= . 12.将一副直角三角板按图示方法放置(直角顶点重合), 则AOB DOC ∠+∠= .13.已知不等式组13(1)022x ax x <⎧⎪⎨⎛⎫---> ⎪⎪⎝⎭⎩的解集为2x <,则a 的取值范围是 . 14.已知实数a b ,在数轴上的位置如图所示,则以下三个命题:(1)320a ab -<,(2a b =+,(3)11a b a<-, 其中真命题的序号为 .15.关于x 的一元二次方程2(1)10m x mx --+=有两个不相等的实数根,则m 的取值范围是 .16.如图,已知直角三角形ACB ,3AC =,4BC =, 过直角顶点C 作1CA AB ⊥,垂足为1A ,再过1A 作11AC BC ⊥, 垂足为1C ;过1C 作12C A AB ⊥,垂足为2A ,再过2A 作22A C BC ⊥,垂足为2C ;……,这样一直做下去,得到了xA .xB .xD . xC .A .B .C .D .CDAOB30°45°aAC B A 1 A 2A3A 4 A 5 C 1C 2 C 3 C 4 C 5一组线段1CA ,11AC ,12C A ,……,则第10条线段55A C = .三、解答题(本大题包括9个小题,共72分,解答应写出必要的演算步骤,证明过程或文字说明)17.(本题6112cos60(2-⎛⎫+ ⎪⎝⎭.18.(本题6分)如图,两幢楼高30mAB CD ==,两楼间的距离24m AC =,当太阳光线与水平线的夹角为30时,求甲楼投在乙楼上的影子的高度.(结果精确到0.01,1.732 1.414)19.(本题7分)将图(1)中的矩形ABCD 沿对角线AC 剪开,再把ABC △沿着AD 方向平移,得到图(2)中的A B C '''△.其中E 是A B ''与AC 的交点,F 是A C ''与CD 的交点.在图(2)中除ADC △与C B A '''△全等外,还有几对全等三角形(不得添加辅助线和字母)?请一一指出,并选择其中一对证明.20.(本题7分)阅读材料,解答问题材料:利用解二元一次方程组的代入消元法可解形如221(1)21(2)x y x y ⎧+=⎪⎨⎪-=⎩……………的方程组. 如:由(2)得1y x =-,代入(1)消元得到关于x 的方程:A B CD A CD E F B ' A ' 图(1) 图(2)CA2104x x -+=,1212x x ∴== 将1212x x ==代入1y x =-得:1212y y ==-,∴方程组的解为12121212x x y y ⎧==⎪⎪⎨⎪==-⎪⎩请你用代入消元法解方程组:222(1)21(2)x y x y +=⎧⎨-=⎩……………21.(本题10分)学校要从甲、乙、丙三名中长跑运动员中选出一名奥运火炬传递手.先对三人一学期的1000米测试成绩作了统计分析如表一;又对三人进行了奥运知识和综合素质测试,测试成绩(百分制)如表二;之后在100人中对三人进行了民主推选,要求每人只推选1人,不准弃权,最后统计三人的得票率如图三,一票计2分.(1)请计算甲、乙、丙三人各自关于奥运知识,综合素质,民主推选三项考查得分的平均成绩,并参考1000米测试成绩的稳定性确定谁最合适.(2)如果对奥运知识、综合素质、民主推选分别赋予3,4,3的权,请计算每人三项考查的平均成绩,并参考1000米测试的平均成绩确定谁最合适.表一图三22.(本题8分)如图,已知O 为坐标原点,点A 的坐标为(23),,A 的半径为1,过A 作直线l 平行于x 轴,点P 在l 上运动.(1)当点P 运动到圆上时,求线段OP 的长. (2)当点P 的坐标为(43),时,试判断直线OP 与A 的位置关系,并说明理由.23.(本题8分)如图正方形OABC 的面积为4,点O 为坐标原点,点B 在函数ky x=(0k <,0x <)的图象上,点()P m n ,是函数(00)ky k x x=<<,的图象上异于B 的任意一点,过点P 分别作x 轴,y 轴的垂线,垂足分别为E F ,.(1)设矩形OEPF 的面积为1S ,判断1S 与点P 的位置是否有关(不必说理由). (2)从矩形OEPF 的面积中减去其与正方形OABC 重合的面积,剩余面积记为2S ,写出2S 与m 的函数关系,并标明m 的取值范围.24.(本题10分)冷饮店每天需配制甲、乙两种饮料共50瓶,已知甲饮料每瓶需糖14克,柠檬酸5克;乙饮料每瓶需糖6克,柠檬酸10克.现有糖500克,柠檬酸400克. (1)请计算有几种配制方案能满足冷饮店的要求?(2)冷饮店对两种饮料上月的销售情况作了统计,结果如下表.请你根据这些统计数据确25.(本题10分)如图已知二次函数图象的顶点坐标为(11)C ,,直线y kx m =+的图象与该二次函数的图象交于A B ,两点,其中A 点坐标为51324⎛⎫ ⎪⎝⎭,,B 点在y 轴上,直线与x 轴的交点为F .P 为线段AB 上的一个动点(点P 与A B ,不重合),过P 作x 轴的垂线与这个二次函数的图象交于E 点.(1)求k m ,的值及这个二次函数的解析式;(2)设线段PE 的长为h ,点P 的横坐标为x ,求h 与x 之间的函数关系式,并写出自变量x 的取值范围;(3)D 为直线AB 与这个二次函数图象对称轴的交点,在线段AB 上是否存在点P ,使得以点P E D ,,为顶点的三角形与BOF △相似?若存在,请求出P 点的坐标;若不存在,请说明理由.2008年呼和浩特市中考试卷 数学参考答案及评分标准二、填空题(本大题共6个小题,每小题3分,共18分) 11.392x -12.18013.2a ≥14.(1)(3)(只填一个不给分)15.2m ≠且1m ≠(只填一个不给分) 16.10435⎛⎫⨯ ⎪⎝⎭三、解答题(本大题9个小题,共72分) 17.解:原式1222=+⨯π+112=++ ······································································································· 4分 4=+π ···································································································································· 6分18.解:延长MB 交CD 于E ,连结BD 由于30AB CD ==NB ∴和BD 在同一直线上30DBE MBN ∴∠=∠=四边形ACDB 是矩形 24BD AC ∴== ··················································································································· 3分 在Rt BED △中tan 30DEBD=tan 30243DE BD ==⨯=3016.14CE ∴=- ···································································································· 5分 ∴投到乙楼影子高度是16.14m . ·························································································· 6分 19.(1)AA E C CF ''△≌△ ································································································ 2分(2)A DF CB E ''△≌△ ····································································································· 4分 证明:(1)四边形ABCD 是矩形 AD BC ∴∥DAC ACB ∴∠=∠由平移的性质得:ACB C '∠=∠,AA CC ''=,90AA E C CF ''∠=∠=,DAC C '∴∠=∠30° MBND CA 30°EAA E C CF ''∴△≌△ ············································································································ 7分 (2)四边形ABCD 是矩形AD B C ''∴=,且DAC ACB ∠=∠由平移的性质得AA CC ''=,90D B '∠=∠=,ACB C '∠=∠A DBC ''∴=又DA F C ''∠=∠,ECB DAC '∠=∠ DA F ECB ''∴∠=∠ A DF CB E ''∴△≌△ ············································································································ 7分20.解:由(1)得2y x =-,代入(2)得222(2)1x x --=化简得:2450x x +-=(5)(1)0x x +-=15x =-,21x = ····················································································································· 4分 把15x =-,21x =分别代入2y x =-得:17y =,21y = ······················································································································ 6分 1157x y =-⎧∴⎨=⎩ 2211x y =⎧⎨=⎩···································································································································· 7分 21.(1)甲民主得分10025250=⨯⨯=% 乙民主得分10035270=⨯⨯=% 丙民主得分10040280=⨯⨯=% ·························································································· 2分甲三项平均成绩857550703++==乙三项平均成绩608070703++== 丙三项平均成绩706080703++== ···················································································· 4分2 3.5S =甲,2 2.5S =乙,2 1.5S =丙222S S S ∴>>乙甲丙,而甲,乙,丙三项考查平均成绩相同. ∴选择丙最合适. ·················································································································· 6分如果用极差说明选丙也给分.(2)甲平均数85375450370.5343⨯+⨯+⨯==++ ··································································· 7分乙平均数60380470371343⨯+⨯+⨯==++ ··············································································· 8分丙平均数70360480369343⨯+⨯+⨯==++ ··············································································· 9分∴乙平均数>甲平均数>丙平均数,而三人的平均测试成绩相同.∴选择乙最合适. ················································································································ 10分 22.解:(1)如图,设l 与y 轴交点为C 当点P 运动到圆上时,有12P P ,两个位置1OP ∴==2OP == ····························································· 4分 (2)连接OP ,过A 作AM OP ⊥,垂足为(43)P ,4CP ∴=,2AP =在Rt OCP △中,5OP =APM OPC ∠=∠,PMA PCO ∠=∠=PAM POC ∴△∽△ ··································6分PA AMPO OC ∴= 253AM = 615AM ∴=>∴直线OP 与A 相离. ······································································································· 8分 23.解:(1)没有关系 ··········································································································· 2分(2)正方形OABC 的面积为4 2OC OA ∴==(22)B ∴-, 把(22)B -,代入ky x=中 22k=-,4k ∴=- ∴解析式为4y x=- ················································································································ 4分 l()P m n ,在4y x=-的图象上, 4n m∴=-①当P 在B 点上方时24()2()S m m m=----42(20)m m =+-<< ················································· 6分②当P 在B 点下方时,2442S m m m ⎛⎫⎛⎫=---- ⎪ ⎪⎝⎭⎝⎭84(2)m m=+<- ··················································································································· 8分 24.解:(1)设配制甲种饮料x 瓶,则乙种饮料为(50)x -瓶 ··········································· 1分 由题意得:146(50)500510(50)400x x x x +-⎧⎨+-⎩≤≤ ········································································································ 4分 解得:2025x ≤≤ ·············································································································· 5分x 只能取整数,∴共有6种方案.····················································································· 6分 x ∴=20,21,22,23,24,25(可以不写) 50x -=30,29,28,27,26,25(注意:没有写出具体哪6种方案不扣分) (2)配制方案为:50瓶中,甲种配制21瓶,乙种配制29瓶. ········································································ 8分 理由:甲的众数是21,乙的众数是29∴这样配制更能满足顾客需求. ························································································· 10分 (注意:只要理由充分,可酌情给分.) 25.解:(1)设抛物线解析式为2(1)1y a x =-+51324A ⎛⎫⎪⎝⎭,在抛物线上, 21351142a ⎛⎫∴=-+ ⎪⎝⎭1a ∴= ∴二次函数解析式为:2(1)1y x =-+(或222y x x =-+) ················································································· 1分 令0x =得:2y =即(02)B ,点在y kx m =+上 2m ∴= 把51324⎛⎫ ⎪⎝⎭,代入2y kx =+得12k =··················(2)212(1)12h x x =+--- 212222x x x =+-+- 255022x x x ⎛⎫=-+<< ⎪⎝⎭········································································································ 4分 (3)假设存在点P ,①当90PED BOF ∠=∠=时,由题意可得PED BOF △∽△,则251224x x x -+-= 22x ∴=,502x <<,22x ∴=舍去 而52x =<,∴存在点P ,其坐标为21024⎛+ ⎝⎭,. ·································· 6分 ②当90PDE BOF ∠=∠=时,过点E 作EK 垂直于抛物线的对称轴,垂足为K ;由题意可得:PDE EKD △∽△ P D E B O F △∽△ E K D B O F ∴△∽△ 则25(22)1242x x x --+-= 2x ∴=± 502x <<,x =(舍去) 而522x =<,∴存在点P ,其坐标为⎝⎭. ··········································· 9分 ∴综上所述存在点P 满足条件,其坐标为⎝⎭,⎝⎭ 10分。