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北京市西城区2022—2023学年度第一学期期末试卷九年级数学第1页(共7页)北京市西城区2022—2023学年度第一学期期末试卷九年级数学2023.1第一部分选择题一、选择题(共16分,每题2分)第1-8题均有四个选项,符合题意的选项只有一个.
1.二次函数2(2)3yx的最小值是(A)3(B)2(C)3(D)22.中国传统扇文化有着深厚的文化底蕴,是中华民族文化的一个组成部分.在中国传统社会中,扇面形状的设计与日常生活中的图案息息相关.下列扇面图形中,既是轴对称图形,又是中心对称图形的是(A)(B)(C)(D)3.下列事件
中是随机事件的是(A)明天太阳从东方升起(B)经过有交通信号灯的路口时遇到红灯(C)平面内不共线的三点确定一个圆(D)任意画一个三角形,其内角和是540°注意事项1.本试卷共7页,共两部分,28道题。满分100分。考试时间120分钟。2.在试卷和答题卡上准确填
写学校、班级、姓名和学号。3.试题答案一律填涂或书写在答题卡上,在试卷上作答无效。4.在答题卡上,选择题、作图题用2B铅笔作答,其他试题用黑色字迹签字笔作答。5.考试结束,请将考试材料一并交回。北京市西城区2022—2023学年度第一学期期末
试卷九年级数学第2页(共7页)4.如图,在⊙O中,弦AB,CD相交于点P,∠A=45°,∠APD=80°,则∠B的大小是(A)35°(B)45°(C)60°(D)70°5.抛物线221yx通过变换可以得到抛物线22(1)3yx,以下变换过程正确的是(A)先向右
平移1个单位,再向上平移2个单位(B)先向左平移1个单位,再向下平移2个单位(C)先向右平移1个单位,再向下平移2个单位(D)先向左平移1个单位,再向上平移2个单位6.要组织一次篮球联赛,赛制为单循环形式(每两队之间都只赛一场),计划安排15场比赛.如果设邀请x个球
队参加比赛,那么根据题意可以列方程为(A)215x(B)(1)15xx(C)(1)15xx(D)(1)152xx7.如图,在等腰△ABC中,∠A=120°,将△ABC绕点C逆时针旋转α(0°<α<90°)得到△CDE,当点A的对应点D落在
BC上时,连接BE,则∠BED的度数是(A)30°(B)45°(C)55°(D)75°8.下表记录了二次函数22yaxbx(0a)中两个变量x与y的5组对应值,其中121xx.x…51x2x13…y…m020m…根据表中信息,当
502x时,直线yk与该二次函数图象有两个公共点,则k的取值范围是(A)726k(B)76<k≤2(C)823k(D)2<k≤83北京市西城区2022—2023学年度第一学期期末试卷九年级数学第3页(共7页)第二部分非选择题二、填空题(共16分,每题2分
)9.一元二次方程2160x的解是____.10.已知⊙O的半径为5,点P到圆心O的距离为8,则点P在⊙O______(填“内”“上”或“外”).11.若关于x的一元二次方程230xxc有两个相等的实数根,则c的值为_____.12
.圆心角是60°的扇形的半径为6,则这个扇形的面积是_____.13.点M(3,m)是抛物线2yxx上一点,则m的值是______,点M关于原点对称的点的坐标是______.14.已知二次函数满足条件:①图象过原点;②当x>1时
,y随x的增大而增大.请你写出一个满足上述条件的二次函数的解析式:______.15.如图,在平面直角坐标系xOy中,以点A(2,0)为圆心,1为半径画圆.将⊙A绕点O逆时针旋转α(0°<α<180°)得到⊙A,使得⊙A与y轴相切,则α的度数是____.16.如图,AB是
⊙O的直径,C为⊙O上一点,且ABOC,P为圆上一动点,M为AP的中点,连接CM.若⊙O的半径为2,则CM长的最大值是_____.北京市西城区2022—2023学年度第一学期期末试卷九年级数学第4页(共7页)三、解答题(共
68分,第17-18题,每题5分,第19题6分,第20-23题5分,第24-26题,每题6分,第27-28题,每题7分)解答应写出文字说明、演算步骤或证明过程.17.解方程:2420xx.18.已知:点A,B,C在⊙O上,且∠BAC=45°.求作:直
线l,使其过点C,并与⊙O相切.作法:①连接OC;②分别以点B,点C为圆心,OC长为半径作弧,两弧交于⊙O外一点D;③作直线CD.直线CD就是所求作直线l.(1)使用直尺和圆规,依作法补全图形(保留作图痕
迹);(2)完成下面的证明.证明:连接OB,BD,∵OB=OC=BD=CD,∴四边形OBDC是菱形.∵点A,B,C在⊙O上,且∠BAC=45°,∴∠BOC=______°(_________________)(填推理的依据).∴四边形OBDC是正方形.∴
∠OCD=90°,即OC⊥CD.∵OC为⊙O半径,∴直线CD为⊙O的切线(_________________)(填推理的依据).北京市西城区2022—2023学年度第一学期期末试卷九年级数学第5页(共7页)19.已知二
次函数223yxx.(1)将223yxx化成2()yaxhk的形式,并写出它的顶点坐标;(2)在所给的平面直角坐标系中画出此函数的图象;(3)当-1<x<2时,结合图象,直接写出函数值y的取值范围.20.如图,AB是⊙O的一条弦,点C是AB的中点,连接OC并延长交
劣弧AB于点D,连接OB,DB.若AB=4,CD=1,求△BOD的面积.21.在学习《用频率估计概率》时,小明和他的伙伴们设计了一个摸球试验:在一个不透明帆布袋中装有白球和红球共4个,这4个球除颜色外无其他差别.每次摸球前先将袋中的球搅匀,然后从袋中随机摸出1个球,观察该球的颜色并记录,再把它放
回.在老师的帮助下,小明和他的伙伴们用计算机模拟这个摸球试验.下图显示的是这个试验中摸出一个球是红球的结果.(1)根据所学的频率与概率关系的知识,估计从这个不透明的帆布袋中随机摸出一个球是红球的概率是,其中红球的个数是;
(2)如果从这个不透明的帆布袋中同时摸出两个球,用列举法求摸出的两个球刚好一个是红球和一个是白球的概率.北京市西城区2022—2023学年度第一学期期末试卷九年级数学第6页(共7页)22.如图,在四边形ABCD中,AC,B
D是对角线,将点B绕点C逆时针旋转60°得到点E,连接AE,BE,CE.(1)求∠CBE的度数;(2)若△ACD是等边三角形,且∠ABC=30°,AB=3,BD=5,求BE的长.23.已知关于x的方程22290xmxm.(1)求证:方程有两个不相等的实数根;(2)设此方程的两个根分别为
1x,2x,且12xx,若1225xx,求m的值.24.如图,在△ABC中,AB=AC,∠BAC=90°,点O是AC上一点,以O为圆心,OA长为半径作圆,使⊙O与BC相切于点D,与AC相交于点E.过点B作BF∥AC,交ED的延长
线于点F.(1)若AB=4,求⊙O的半径;(2)连接BO,求证:四边形BFEO是平行四边形.25.跳台滑雪是冬季奥运会的比赛项目之一.如图,运动员通过助滑道后在点A处起跳经空中飞行后落在着陆坡BC上的点P处,他在空中飞行的路线可
以看作抛物线的一部分.这里OA表示起跳点A到地面OB的距离,OC表示着陆坡BC的高度,OB表示着陆坡底端B到点O的水平距离.建立如图所示的平面直角坐标系,从起跳到着陆的过程中,运动员的竖直高度y(单位:m)与水平距离x(单
位:m)近似满足函数关系:2116yxbxc.已知OA=70m,OC=60m,落点P的水平距离是40m,竖直高度是30m.(1)点A的坐标是_____,点P的坐标是_______;(2)求满足的
函数关系2116yxbxc;(3)运动员在空中飞行过程中,当他与着陆坡BC竖直方向上的距离达到最大时,直接写出此时的水平距离.北京市西城区2022—2023学年度第一学期期末试卷九年级数学第7页(共7页)26.在平面直角坐标系xOy中,抛物线2yaxbxc
(a≠0)的对称轴为直线x=t,且320abc.(1)当0c时,求t的值;(2)点1(2)y,,2(1)y,,3(3)y,在抛物线上,若a>c>0,判断1y,2y与3y的大小关系,并说明理由.27.如图,在△ABC中,AC=BC,∠ACB=90°,∠APB=45°,连接CP,将线段CP
绕点C顺时针旋转90°得到线段CQ,连接AQ.(1)依题意,补全图形,并证明:AQ=BP;(2)求∠QAP的度数;(3)若N为线段AB的中点,连接NP,请用等式表示线段NP与CP之间的数量关系,并证明.28.给定图形W和点P,Q,若图形W
上存在两个不重合的点M,N,使得点P关于点M的对称点与点Q关于点N的对称点重合,则称点P与点Q关于图形W双对合.在平面直角坐标系xOy中,已知点A(-1,-2),B(5,-2),C(-1,4).(1)在点D(-4,0),E(2,2),F(6,
0)中,与点O关于线段AB双对合的点是;(2)点K是x轴上一动点,⊙K的直径为1,①若点A与点T(0,t)关于⊙K双对合,求t的取值范围;②当点K运动时,若△ABC上存在一点与⊙K上任意一点关于⊙K双对合,直接写出点K的横坐标k的取值范围.
北京市西城区2022—2023学年度第一学期期末试卷九年级数学答案及评分参考2023.1一、选择题(共16分,每题2分)题号12345678答案ACBADDBC二、填空题(共16分,每题2分)9.14x,24x.10.外.11.94.12.6.13.6,(-3,-6).14
.答案不唯一,如:22yxx.15.45°或135°.16.51.三、解答题(共68分,第17-18题,每题5分,第19题6分,第20-23题5分,第24-26题,每题6分,第27-28题,每题7分)17.解:1a,4b,2c.·····
··································································1分224(4)4128bac>0.············
····························································2分方程有两个不相等的实数根242bbacxa4821···········································
·············································4分22.原方程的根为122x,222x.···················································
··············5分18.解:(1)补全图形,如图所示;······················································································2分
(2)90°,一条弧所对的圆周角等于它所对的圆心角的一半,经过半径的外端并且垂直于这条半径的直线是圆的切线.········································5分19.解:(1)223yxx
22113xx2(1)4x.顶点坐标是(1,-4);····················································································2分(2)
图象如图所示;········································4分(3)-4≤y<0.·················································6分20.解:设OD=x
,则OB=x.∵点C是AB的中点,OC过圆心O,∴OC⊥AB.··············································1分∵AB=4,CD=1,∴122BCAB,OC=OD-CD=x-1.····················
······························2分∵在Rt△BCO中,OB2=OC2+BC2,∴222(1)2xx.········································································
···············3分解得,52x.∴52OD.·······················································································
···················4分∴1522BODSODBC.···········································································5分21.解:(1)0.75,3;····
·································································································2分(2)由(1)可知帆布袋中有3个红球和1个白球.列表如下:可以看出,从帆布袋中同时摸出两个球,所
有可能出现的结果共有6种,即(白,红1),(白,红2),(白,红3),(红1,红2),(红1,红3),(红2,红3),且这些结果出现的可能性相等,其中摸出的两个球刚好一个是红球和一个是白球(记为事件A)共有3种结果,即(白,红
1),(白,红2),(白,红3),所以31()62PA.······································································5分22.解:(1)∵将点B绕点C逆时针旋转60°得到点E,∴C
B=CE,∠BCE=60°.∴△BCE是等边三角形.∴∠CBE=60°.................................................................................
..............2分(2)∵△ACD是等边三角形,∴AC=DC,∠ACD=60°.∴∠ACE=∠DCB.又∵CB=CE,∴△ACE≌△DCB.∴AE=BD.∵BD=5,∴AE=5.∵∠CBE=60°,
∠ABC=30°,∴∠ABE=90°.∴在Rt△ABE中,22BEAEAB.∵AB=3,∴BE=4.···································································
······································5分23.(1)证明:Δ22(2)41(9)mm·························································
···············1分224436mm36>0.∴方程有两个不相等的实数根.······················································2分(2)解:解方程,得2362622mmx,··
·······························································3分∵12xx,∴13xm,23xm.······················
···········································4分∵1225xx,∴2(3)35mm.∴4m.·····································································
·····································5分24.(1)解:连接OD,如图1.∵在△ABC中,AB=AC,∠BAC=90°,∴⊙O与AB相切于点A,∠ACB=45°.∵OD是⊙O的半径,⊙O与BC相切于点D,∴OD⊥BC.∴∠ODC=90°,OD=
DC.∵AB=4,∴BD=AB=4,42BC.∴424ODDC.∴⊙O的半径是424.·································································
···············3分(2)证明:连接AD,交OB于点H,如图2.∵AE是⊙O的直径,∴∠ADE=90°.∵AB,BC与⊙O分别相切于点A,D,∴BD=AB,∠ABO=∠DBO.∴OB⊥AD.∴∠AHO=90°.∴∠AHO=∠ADE.∴OB∥EF.∵BF∥AC,∴
四边形BFEO是平行四边形.····································································6分25.解:(1)A(0,70),P(40,30).·························
························································2分(2)∵A(0,70),∴c=70.所以函数关系2116yxbxc化为217016yxbx
.∵点P的坐标是(40,30),∴214040703016b.图1图2解得32b.所以函数关系是21370162yxx.·························································
··4分(3)18m.····························································································
·······················6分26.解:(1)当0c时,得320ab.∴324bta.··········································
····················································2分(2)∵320abc,∴3244bctaa.∵a>c>0,∴0<4ca<14.∴34
<t<1.······································································································4分∵点1(2)y,关于直线x=t的对称点的坐标是1(22)ty
,,∴72<22t<4.∴1<3<22t.∵a>0,∴当x>t时,y随x的增大而增大.∴2y<3y<1y.························································································
······6分27.(1)补全图形,如图1.证明:∵线段CP绕点C顺时针旋转90°得到线段CQ,∴CP=CQ,∠PCQ=90°.∵∠ACB=90°,∴∠BCP=∠ACQ.∵AC=BC,∴△BCP≌△ACQ.∴AQ=BP.·····································
························································2分图1(2)解:连接QP,如图2.由(1)可得△PCQ是等腰直角三角形,∴∠CQP=∠CPQ=45°.∴∠CQA+
∠PQA=45°.∵∠APB=45°,∴∠APQ=∠CPB.由△BCP≌△ACQ可得∠CQA=∠CPB.∴∠APQ+∠PQA=45°.∴∠QAP=135°.··············································
·················4分(3)CP=2NP.证明:延长PN至K,使得NK=PN,连接AK,如图3.∵N为线段AB的中点,∴AN=BN.∵∠ANK=∠BNP,∴△ANK≌△BNP.∴∠KAN=∠PBN,AK=BP.∴AK∥BP,AK=AQ.∴∠KAP+∠APB=180°.∵∠A
PB=45°,∴∠KAP=135°.∵∠QAP=135°,∴∠KAP=∠QAP.∵AP=AP,∴△KAP≌△QAP.∴KP=QP.∵在等腰直角△PCQ中,CP=CQ,∴KP=QP=2CP.∵KP=2NP,∴CP=2NP.·······
···········································································7分图3图228.解:(1)D,F;································
·····································································2分(2)①设GH是⊙K上任意一条直径,则GH=1.设点1A是与点A关于⊙K双对合的点,将点A和点1A分别关于
点G,H对称后重合的点记为2A,所以点G,H分别是2AA和12AA的中点.由三角形中位线的知识,可知1AA=2GH=2.随着点G,H在⊙K上运动,点1A在以点A为圆心,2为半径的圆上及其内部(不含点A),将它记为S.因为点A与点T(0,t)关于⊙K双对合,所以当S
与y轴相交时,可求得t的值为23和23.所以t的取值范围是23≤t≤23.··························5分②52≤k≤12或3322≤k≤3322.··········
········································································································7分