2007年南京数学中考试题
- 格式:doc
- 大小:1.09 MB
- 文档页数:8
2007年南京数学中考试卷一、选择题(每小题2分,共24分)1.计算12-+的值是( ) A.3- B.1- C.1 D.32.2007年5月2日,南京夫子庙、中山陵、玄武湖、雨花台四大景区共接待游客约518 000人,这个数可用科学记数法表示为( ) A.40.51810⨯ B.55.1810⨯C.651.810⨯D.351810⨯3.计算3x x ÷的结果是( ) A.4xB.3xC.2xD.3 4.14的算术平方根是( ) A.12- B.12C.12±D.1165.不等式组2110x x >-⎧⎨-⎩,≤的解集是( )A.12x >-B.12x <-C.1x ≤D.112x -<≤6.反比例函数2k y x=-(k 为常数,0k ≠)的图象位于( )A.第一、二象限 B.第一、三象限 C.第二、四角限D.第三、四象限7.如图,一个可以自由转动的转盘被等分成6个扇形区域,并涂上了相应的颜色,转动转盘,转盘停止后,指针指向黄色区域的概率是( ) A.16B.13C.12D.238.下列轴对称图形中,对称轴条数最少的是( ) A.等边三角形 B.正方形 C.正六边形 D.圆 9.下列四个几何体中,已知某个几何体的主视图、左视图、俯视图分别为长方形、长方形、圆,则该几何体是( ) A.球体 B.长方体 C.圆锥体 D.圆柱体 10.如果a ∠是等腰直角三角形的一个锐角,则tan α的值是( ) A.12B.22C.1D.211.下列各数中,与23的积为有理数的是( ) A.23+B.23-C.23-+D.312.如图,在平面直角坐标系中,点P 在第一象限,P 与x 轴相切于点Q ,与y 轴交于(02)M ,,(08)N ,两点,则点P 的坐标是( )A.(53),B.(35),C.(54),D.(45),二、填空题(每小题3分,共12分)13.如果40a ∠=,那么a ∠的补角等于.蓝 蓝 红红 红 黄(第7题)QPONxyM(第12题)BO(第15题)CA14.已知5筐苹果的质量分别为(单位:kg );5249505351,,,,,则这5筐苹果的平均质量为kg .15.如图,O 是ABC △的外接圆,30C ∠=,2cm AB =,则O 的半径为cm .16.已知点()P x y ,位于第二象限,并且4y x +≤,x y ,为整数,写出一个..符合上述条件的点P 的坐标:.三、计算题(每小题6分,共18分)17.解方程组42 5.x y x y +=⎧⎨-=⎩,18.计算:221111a a a a a a -÷----. 19.某养鸡场分3次用鸡蛋孵化出小鸡,每次孵化所用的鸡蛋数、每次的孵化率(孵化率=100%⨯孵化出的小鸡数孵化所用的鸡蛋数)分别如图1,图2所示:(1)求该养鸡场这3次孵化出的小鸡总数和平均孵化率;(2)如果要孵化出2000只小鸡,根据上面的计算结果,估计该养鸡场要用多少个鸡蛋?四、解答题(第20题8分,第21题6分,第22题7分,共21分)20.两组邻边分别相等的四边形我们称它为筝形. 如图,在筝形ABCD 中,AB AD =,BC DC =,AC ,BD 相交于点O , (1)求证:①ABC ADC △≌△; ②OBOD =,AC BD ⊥;(2)如果6AC =,4BD =,求筝形ABCD 的面积.21.将A B C D ,,,四人随机分成甲、乙两组参加羽毛球比赛,每组两人.(1)A 在甲组的概率是多少?(2)A B ,都在甲组的概率是多少?22.如图,A B ,两地之间有一座山,汽车原来从A 地到B 地须经C 地沿折线A C B --行驶,现开通隧道后,汽车直接沿直线AB 行驶.已知10km AC =,30A ∠=,45B ∠=,则隧道开通后,汽车从A 地到B 地比原来少走多少千米?(结果精确到0.1km )(参考数据:2 1.41≈,3 1.73≈)O D A B CC AB304510 20 30 40 50 60 70 405060鸡蛋数/个 批次第3次 第2次 第1次 0图1孵化出用的鸡蛋数统计图 60% 70% 80% 90% 40%50% 孵化率批次第3次第2次 第1次 图2孵化率统计图82.5% 78% 80%五、(每小题7分,共14分)23.某市为了鼓励居民节约用水,采用分段计费的方法按月计算每户家庭的水费,月用水量不超过203m 时,按2元/3m 计费;月用水量超过203m 时,其中的203m 仍按2元/3m 收费,超过部分按2.6元/3m 计费.设每户家庭用用水量为3m x 时,应交水费y 元.(1)分别求出020x ≤≤和20x >时y 与x 的函数表达式;(2)小明家第二季度交纳水费的情况如下: 月份 四月份 五月份 六月份 交费金额 30元 34元 42.6元 小明家这个季度共用水多少立方米?24.如图,A 是半径为12cm 的O 上的定点,动点P 从A 出发,以2πcm/s 的速度沿圆周逆时针运动,当点P 回到A 地立即停止运动. (1)如果90POA ∠=,求点P 运动的时间;(2)如果点B 是OA 延长线上的一点,AB OA =,那么当点P 运动的时间为2s 时,判断直线BP 与O 的位置关系,并说明理由.六、(每小题7分,共14分)25.某农场去年种植了10亩地的南瓜,亩产量为2000kg ,根据市场需要,今年该农场扩大了种植面积,并且全部种植了高产的新品种南瓜,已知南瓜种植面积的增长率是亩产量的增长率的2倍,今年南瓜的总产量为60 000kg ,求南瓜亩产量的增长率. 26.在梯形ABCD 中,AD BC ∥,6AB DC AD ===,60ABC ∠=,点E F ,分别在线段AD DC ,上(点E 与点A D ,不重合),且120BEF ∠=,设A E x =,DF y =.(1)求y 与x 的函数表达式;(2)当x 为何值时,y 有最大值,最大值是多少?AP BOA ED FCB七、(本题10分)27.在平面内,先将一个多边形以点O 为位似中心放大或缩小,使所得多边形与原多边形对应线段的比为k ,并且原多边形上的任一点P ,它的对应点P '在线段OP 或其延长线上;接着将所得多边形以点O 为旋转中心,逆时针旋转一个角度θ,这种经过和旋转的图形变换叫做旋转相似变换,记为()O k θ,,其中点O 叫做旋转相似中心,k 叫做相似比,θ叫做旋转角. (1)填空:①如图1,将ABC △以点A 为旋转相似中心,放大为原来的2倍,再逆时针旋转60,得到ADE △,这个旋转相似变换记为A (,);②如图2,ABC △是边长为1cm 的等边三角形,将它作旋转相似变换(390)A ,,得到ADE △,则线段BD 的长为cm ;(2)如图3,分别以锐角三角形ABC 的三边AB ,BC ,CA 为边向外作正方形ADEB ,BFGC ,CHIA ,点1O ,2O ,3O 分别是这三个正方形的对角线交点,试分别利用12AO O △与ABI △,CIB △与2CAO △之间的关系,运用旋转相似变换的知识说明线段12O O 与2AO 之间的关系.八、(本题7分)28.已知直线l 及l 外一点A ,分别按下列要求写出画法,并保留两图痕迹. (1)在图1中,只用圆规....在直线l 上画出两点B C ,,使得点A B C ,,是一个等腰三角形的三个顶点; (2)在图2中,只用圆规....在直线l 外画出一点P ,使得点A P ,所在直线与直线l 平行.A I图1A I图2C ABDE图1ABCDE图2EDBFGCHAI3O1O2O图3南京市2007年初中毕业生学业考试 数学试题参考答案及评分标准一、选择题(每小题2分,共24分)题号1 2 3 4 5 6 7 8 9 10 11 12 答案C B C BD CBADCAD 二、填空题(每小题3分,共12分)13.140 14.51 15.2 16.(13)-,,(12)-,,(11)-,,(21)-,,(22)-,,(31)-,六个中任意写出一个即可三、(每小题6分,共24分) 17.(本题6分)解:①+②,得39x =. 解得3x =. ··························································································································· 3分把3x =代入②,得1y =. ··································································································· 5分∴原方程组的解是31x y =⎧⎨=⎩,. ································································································· 6分 18.(本题6分) 解:原式221111a a a a a a -=---- ···························································································· 2分 (1)(1)11(1)1a a a a a a a -+=---- ································································································· 4分 1111a a a +=--- ······················································································································· 5分1a a =-. ································································································································ 6分19.(本题6分)解:(1)该养鸡场这3次孵化出的小鸡总数为4082.550786080120⨯+⨯+⨯=%%%(只). ··························································································································· 2分这3次的平均孵化率为12010080405060⨯=++%%. ······················································· 4分(2)2000802500÷= % (个). ∴估计该养鸡场要用2 500个鸡蛋. ···················································································· 6分四、(第20题8分,第21题6分,第22题7分,满分21分) 20.证明:(1)①在ABC △和ADC △中,AB AD =,BC DC =,AC AC =, ··············································································· 2分ABC ADC ∴△≌△. ········································································································· 3分②ABC ADC △≌△, EAO DAO ∴=∠∠. ·········································································································· 4分AB AD =, OB OD ∴=,AC BD ⊥. ································································································· 6分(2)筝形ABCD 的面积 ABC =△的面积+ACD △的面积1122AC BO AC DO =⨯⨯+⨯⨯ 116422AC BD =⨯⨯=⨯⨯ 12=. ···································································································································· 8分21.(本题6分)解:所有可能出现的结果如下: 甲组 乙组 结果ABCD (AB CD ,) AC BD (AC BD ,) ADBC (AD BC ,) BC AD (DC AD ,) BD AC (BD AC ,) CD AB (CD AB ,) 总共有6种结果,每种结果出现的可能性相同.(1)所有的结果中,满足A 在甲组的结果有3种,所以A 在甲组的概率是12, ············ 2分 (2)所有的结果中,满足A B ,都在甲组的结果有1种,所以A B ,都在甲组的概率是16. ······················································································ 6分22.(本题7分)解:过点C 作CD AB ⊥,垂足为D . ··············································································· 1分 在Rt CAD △中,30A =∠,10km AC =,15km 2CD AC ∴==, cos3053km AD AC ==. ···························································································· 3分 在Rt BCD △中,45B =∠,5km BD CD ∴==,52km sin 45CD BC ==. ···································································································· 5分(535)km AB AD BD ∴=+=+,1052(535)AC BC AB ∴+-=+-+5525355 1.415 1.73 3.4(km)=+-+⨯-⨯≈≈. ···················································· 6分 答:隧道开通后,汽车从A 地到B 地比原来少走约3.4km . ············································· 7分五、(每小题7分,共14分)23.(本题7分)解:(1)当020x ≤≤时,y 与x 的函数表达式是2y x =;当20x >时,y 与x 的函数表达式是220 2.6(20)y x =⨯+-,即 2.612y x =-; ················································································································· 3分(2)因为小明家四、五月份的水费都不超过40元,六月份的水费超过40元,所以把30y =代入2y x =中,得15x =;把34y =代入2y x =中,得17x =;把42.6y =代入 2.612y x =-中,得21x =. ······································································ 5分所以15172153++=. ······································································································· 6分答:小明家这个季度共用水253m . ···················································································· 7分24.(本题7分)解:(1)当90POA =∠时,点P 运动的路程为O 周长的14或34. 设点P 运动的时间为s t . 当点P 运动的路程为O 周长的14时, 122124t π=π.解得3t =; ···························································································································· 2分当点P 运动的路程为O 周长的34时, 322124t π=π. 解得9t =.∴当90POA =∠时,点P 运动的时间为3s 或9s . ························································· 4分(2)如图,当点P 运动的时间为2s 时,直线BP 与O 相切. ······································ 5分B A PO理由如下:当点P 运动的时间为2s 时,点P 运动的路程为4cm π. 连接OP PA ,.O 的周长为24cm π,AP ∴的长为O 周长的16,60POA ∴=∠.OP OA =,OAP ∴△是等边三角形. OP OA AP ∴==,60OAP =∠, AB OA =,AP AB ∴=. OAP APB B =+∠∠∠,30APB B ∴==∠∠.90OPB OPA APB ∴=+=∠∠∠.OP BP ∴⊥. ∴直线BP 与O 相切. ······································································································· 7分 六、(每小题7分,共14分) 25.(本题7分)解:设南瓜亩产量的增长率为x ,则种植面积的增长率为2x . ········································ 1分 根据题意,得10(12)2000(1)60000x x ++= . ··················································································· 4分解这个方程,得10.5x =,22x =-(不合题意,舍去). ················································· 6分 答:南瓜亩产量的增长率为50%. ······················································································ 7分 26.(本题7分)解:(1)在梯形ABCD 中,AD BC ∥,6AB DC AD ===,60ABC =∠,120A D ∴==∠∠,18012060AEB ABE ∴+=-=∠∠. 120BEF =∠,18012060AEB DEF ∴+=-=∠∠,ABE DEF ∴=∠∠. ABE DEF ∴△∽△. ·········································································································· 2分AE AB DF DE∴=. ····················································································································· 3分AE x =,DF y =,66x y x∴=-. ······················································································································· 4分∴y 与x 的函数表达式是211(6)66y x x x x =-=-+; ······························································································ 5分(2)216y x x =-+213(3)62x =--+. ·············································································································· 6分∴当3x =时,y 有最大值,最大值为32. ········································································· 7分七、(本题10分)27.解:(1)①2,60; ··································································································· 2分②2; ····································································································································· 4分(2)12AO O △经过旋转相似变换(245)A ,,得到ABI △,此时,线段12O O 变为线段BI ;································································································· 6分。