第1页共11页桂林市百色市2009年初中毕业暨升学考试数学试卷一、选择题(每题3分,共36分)1、-8的相反数是()A、-8B、8C、18D、182、下面几个有理数最大的是()11A2BC3D35、、、、3、如图,在所标识的角中,同位角是()A、∠1和∠2B、∠1和∠3C、∠1和∠4D、∠2和∠34、右图是一正四棱锥,它是俯视图是()5、下列运算正确的是()A22Babab22222242、、(-ab)=abC、aa=2aD、aa=26、二次函数y=(x+1)2+2的最小值是()ABCD2、2、1、-3、37、右图是一张卡通图,图中两圆的位置关系是()A、相交B、外离C、内切D、内含8、已知21xy是二元一次方程组71axbyaxby的解,则ab的值为()A、1B、-1C、2D、39、有20张背面完全一样的卡片,其中8张正面印有桂林山水,7张正面印有百色风光,5张正面印有北海海景,把这些卡片的背面朝上搅匀,从中随机抽出一张卡片,抽中正面是桂林山水卡片的概率是()1BCD4A725、、、、205810、如图,在平行四边形ABCD中,AC、BD为对角线,BC=6,BC边上的高为4,则图中阴影部分的面积为()A、3B、6C、12D、24第2页共11页11、如图所示,在方格纸上建立的平面直角坐标系中,将△ABC绕点O按顺时针方向旋转90度,得到△A/B/O,则点A/的坐标为()A、(3,1)B、(3,2)C、(2,3)D、(1,3)12、如图,正方形ABCD的边长为2,将长为2的线段QR的两端放在正方形的相邻的两边上同时滑动。如果点Q从点A出发,沿图中所示方向按A→B→C→D→A滑动到A止,同时点R从点B出发,沿图中所示方向按B→C→D→A→B滑动到B止,在这个过程中,线段QR的中点M所经过的路线围成的图形的面积为()A、2B、4-C、D、1二、填空题(每题3分,共18分)13、因式分解:x2+3x=.14、据统计,去年我国粮食产量达10570亿斤,用科学记数法表示为______亿斤。15、如图,在一次数学课外活动中,测得电线杆底部B与钢缆固定点C的距离为4米,钢缆与地面的夹角为60度,则这条钢缆在电线杆上的固定点A到地面的距离AB是米(结果保留根号)。16、在函数21yx中,自变量x的取值范围是。17、如图,是一个正比例函数的图像,把该图像向左平移一个单位长度,得到的函数图像的解析式为。18、如图,在△ABC中,∠A=,∠ABC的平分线与∠ACD的平分线交于点A1得∠A1,∠A1BC的平分线与∠A1CD的平分线交于点A2,得∠A2,……,∠A2008BC的平分线与∠A2008CD的平分线交于点A2009,得∠A2009,则∠A2009=。第3页共11页三、解答题19、(本题6分)计算:1001200934sin3022-()20、(本题6分)先化简,再求值:2211()22xyxyxxyx,其中x=2,y=321、(本题8分)如图,在等腰梯形ABCD中,AD∥BC,对角线AC、BD相交于点O。(1)图中共有对全等三角形。(2)写出你认为全等的一对三角形,并证明第4页共11页22、(本题8分)2008年11月28日,为扩大内需,国务院决定在全国实施“家电下乡”政策。第一批列入家电下乡的产品为彩电、冰箱、洗衣机和手机四种产品,某县一家家电商场,今年一季度对以上四种产品的销售情况进行了统计,绘制了如下的统计图,请你根据统计图中的信息解答下列问题:(1)该商场一季度彩电销售的数量是台。(2)请补全条形统计图和扇形统计图。23、(本题8分)在保护地球爱护家园活动中,校团委把一批树苗分给初三(1)班同学去栽种,如果每人分2棵,还剩42棵,如果前面每人分3棵,那么最后一人得到的树苗少于5棵(但至少分得一棵)。(1)设初三(1)班有x名同学,则这批树苗有多少棵?(用含x的代数式表示)。(2)初三(1)班至少有多少名同学?最多有多少名同学?第5页共11页24、(本题8分)在我市某一城市美化工程招标时,有甲、乙两个工程队投标,经测算:甲队单独完成这项工程需要60天,若由甲队先做20天,剩下的工程由甲、乙合作24天可完成。(1)乙队单独完成这项工程需要多少天?(2)甲队施工一天,需付工程款3.5万元,乙队施工一天需付工程款2万元。若该工程计划在70天内完成,在不超过计划天数的前提下,是由甲队或乙队单独完成工程省钱?还是由甲乙两队全程合作完成该工程省钱?第6页共11页25、(本题10分)如图,△ABC内接于半圆,AB为直径,过点A作直线MN,若∠MAC=∠ABC。(1)求证:MN是半圆的切线。(2)设D是弧AC的中点,连结BD交AC于G,过D作DE⊥AB于E,交AC于F,求证:FD=FG。(3)若△DFG的面积为4.5,且DG=3,GC=4,试求△BCG的面积。第7页共11页26、(本题12分)如图已知直线L:334yx,它与x轴、y轴的交点分别为A、B两点。(1)求点A、点B的坐标。(2)设F为x轴上一动点,用尺规作图作出⊙P,使⊙P经过点B且与x轴相切于点F(不写作法,保留作图痕迹)。(3)设92)中所作的⊙P的圆心坐标为P(x,y),求y关于x的函数关系式。(4)是否存在这样的⊙P,既与x轴相切又与直线L相切于点B,若存在,求出圆心P的坐标,若不存在,请说明理由。第8页共11页2009年桂林市、百色市初中毕业升学考试数学参考答案及评分标准一、选择题:题号123456789101112答案BACCBADBCCDB二、填空题:13.(3)xx14.1.057×10415.4316.x≥1217.22yx或2(1)yx18.20092三、解答题:19.解:原式=2-1+4×12-2················································································4分=1······························································································6分20.解:原式111()()22xyxyxyxxyxyx·······································2分1122xyxx()·················································································3分()xy····························································································4分yx··································································································5分把23xy,代入上式,得原式=32·················································6分21.解:(1)3…………………………………………………………………………………3分(写1对、2对均不给分)(2)△ABC≌△DCB···········································································4分证明:∵四边形ABCD是等腰梯形∴AB=DC,∠ABC=∠DCB························································6分又BC=CB∴△ABC≌△DCB··································································8分(注:选其它两对证明的,按以上相应步骤给分,全等三角形对应点不对应不扣分)22.解(1)150······················································································(2分)(2)10%························································································(2分)(3)每正确补全一个图形给2分,其中扇形统计图每补全一个扇形给1分.数量(台)20015010050彩电洗衣机冰箱手机品种手机40%洗衣机冰箱20%彩电30%10%第9页共11页23.解(1)这批树苗有(242x)棵······························································1分(2)根据题意,得2423(1)52423(1)1xxxx≥··················································5分(每列对一个不等式给2分)解这个不等式组,得40x≤44································································7分答:初三(1)班至少有41名同学,最多有44名同学.········································8分24.解:(1)设乙队单独完成需x天·································································1分根据题意,得11120()2416060x···········································3分解这个方程,得x=90·····································································4分经检验,x=90是原方程的解∴乙队单独完成需90天··································································5分(2)设甲、乙合作完成需y天,则有11()16090y解得36y(天)················································································6分甲单独完成需付工程款为60×3.5=210(万元)乙单独完成超过计划天数不符题意(若不写此行不扣分).甲、乙合作完成需付工程款为36(3.5+2)=198(万元)·······························7分答:在不超过计划天数的前提下,由甲、乙合作完成最省钱.·······················8分25.证明(1):∵AB是直径∴∠ACB=90º,∴∠CAB+∠ABC=90º·············································1分∵∠MAC=∠ABC∴∠MAC+∠CAB=90º,即MA⊥AB∴MN是半圆的切线.····························2分(2)证法1:∵D是弧AC的中点,∴∠DBC=∠2········3分∵AB是直径,∴∠CBG+∠CGB=90º∵DE⊥AB,∴∠FDG+∠2=90º················4分∵∠DBC=∠2,∴∠FDG=∠CGB=∠FGD∴FD=FG·············································5分证法2:连结AD,则∠1=∠2········