(完整word版)广东省广州市荔湾区2015-2016学年八年级上学期期末考试英语试题(word版附
广州市2015-2016学年八年级上期末数学试卷_
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2015-2016年八年级(上)期末数学试卷一、选择题(共12小题,每小题2分,满分24分,每小题只有一个正确的选项,请将正确选项填入相应的表格内)1.(2014•莱芜)下列四个实数中,是无理数的为()A.0 B.﹣3 C.D.考点:无理数.专题:常规题型.分析:无理数就是无限不循环小数.理解无理数的概念,一定要同时理解有理数的概念,有理数是整数与分数的统称.即有限小数和无限循环小数是有理数,而无限不循环小数是无理数.由此即可判定选择项.解答:解:A、0是整数,是有理数,故A选项错误;B、﹣3是整数,是有理数,故B选项错误;C、=2是无理数,故C选项正确;D、是无限循环小数,是有理数,故D选项错误.故选:C.点评:此题主要考查了无理数的定义,其中初中范围内学习的无理数有:π,2π等;开方开不尽的数;以及像0.1010010001…,等有这样规律的数.2.(2014秋•漳州期末)无理数的整数部分是()A. 1 B. 2 C. 3 D. 4考点:估算无理数的大小.分析:看在哪两个整数之间即可得到它的整数部分.解答:解:∵,∴2<<3,∴的整数部分为2,故选:B.点评:本题考查估算无理数的大小的知识;用“夹逼法”得到无理数的范围是解决本题的关键.3.(2014秋•漳州期末)下列计算正确的是()A.(x3)3=x6B.a6•a4=a24C.(﹣mn)4÷(﹣mn)2=m2n2D.3a+2a=5a2考点:同底数幂的除法;合并同类项;同底数幂的乘法;幂的乘方与积的乘方.分析:根据幂的乘方,底数不变指数相乘;同底数幂相乘,底数不变指数相加;单项式的除法,合并同类项法则对各选项分析判断利用排除法求解.解答:解:A、(x3)3=x3×3=x9,故本选项错误;B、a6•a4=a6+4=a10,故本选项错误;C、(﹣mn)4÷(﹣mn)2=m2n2,故本选项正确;D、3a+2a=5a,故本选项错误.故选C.点评:本题考查了同底数幂的除法,同底数幂的乘法,幂的乘方的性质,合并同类项法则,熟记各性质并理清指数的变化情况是解题的关键.4.(2014秋•漳州期末)观察下列各组数:①9,16,25;②8,15,17;③7,24,25;④12,15,20.其中能作为直角三角形边长的组数为() A.①②B.②③C.③④D.①④考点:勾股定理的逆定理.分析:利用勾股定理的逆定理对四个答案进行逐一判断即可.解答:解:①、错误,∵92+162=337≠252=625,∴不能作为直角三角形边长;②、正确,∵82+152=172=289,∴能作为直角三角形边长;③、正确,∵72+242=252=625,∴能作为直角三角形边长;④、错误,∵122+152=369≠202=400,∴不能作为直角三角形边长.故选B.点评:本题考查的是利用勾股定理的逆定理判断三角形是否为直角三角形,即三角形的三边若满足a2+b2=c2,则此三角形是直角三角形.5.(2014秋•漳州期末)下列命题中正确的是()A.全等三角形的高相等 B.全等三角形的中线相等C.全等三角形的角平分线相等 D.全等三角形对应角相等考点:命题与定理.分析:认真读题,只要甄别,其中A、B、C选项中都没有“对应”二字,都是错误的,只有D是正确的.解答:解:A、全等三角形的对应边上的高相等,故错误;B、全等三角形的对应边上的中线相等,故错误;C、全等三角形的对应角的角平分线相等,故错误;D、全等三角形的对应角相等,正确.故选D.点评:本题考查了全等三角形的性质;注意全等三角形的性质中指的是各对应边上高,中线,角平分线相等.对性质中对应的真正理解是解答本题的关键.6.(2014秋•漳州期末)计算(18x4﹣48x3+6x)÷6x的结果为() A.3x3﹣13x2B.3x3﹣8x2 C.3x3﹣8x2+6x D.3x3﹣8x2+1考点:整式的除法.分析:多项式除以单项式,先把这个多项式的每一项分别除以单项式,再把所得的商相加.解答:解:(18x4﹣48x3+6x)÷6x=3x3﹣8x2+1.故选:D.点评:考查了整式的除法,多项式除以单项式实质就是转化为单项式除以单项式.多项式除以单项式的结果仍是一个多项式.7.(2014秋•漳州期末)若等腰三角形的周长为20,有一边长为4,则它的腰长为()A. 4 B.8 C.10 D.4或8考点:等腰三角形的性质;三角形三边关系.分析:根据等腰三角形的性质分为两种情况解答:当边长4cm为腰或者4cm底边时.解答:解:分情况考虑:当4是腰时,则底边长是20﹣8=12,此时4,4,12不能组成三角形,应舍去;当4是底边时,腰长是(20﹣4)×=8,4,8,8能够组成三角形.此时腰长是8.故选B.点评:本题考查了等腰三角形的性质和三角形的三边关系;已知没有明确腰和底边的题目一定要想到两种情况,分类进行讨论,还应验证各种情况是否能构成三角形进行解答,这点非常重要,也是解题的关键.8.(2014秋•漳州期末)要直观反映我市某一周每天的最高气温的变化趋势,宜采用()A.折线统计图B.条形统计图C.频数分布统计图D.扇形统计图考点:统计图的选择.分析:根据统计图的特点进行分析可得:扇形统计图表示的是部分在总体中所占的百分比,但一般不能直接从图中得到具体的数据;折线统计图表示的是事物的变化情况;条形统计图能清楚地表示出每个项目的具体数目.解答:解:根据题意,要求直观反映我市一周内每天的最高气温的变化情况,结合统计图各自的特点,应选择折线统计图.故选:A.点评:此题主要考查统计图的选择,根据扇形统计图、折线统计图、条形统计图各自的特点来判断.9.(2014秋•漳州期末)如图,有两棵树,一颗高10m,另一颗高5m,两树相距12m,一只鸟从一棵树的树梢飞到另一棵树的树梢,则小鸟至少飞行()A.5m B.10m C.13m D.17m考点:勾股定理的应用.分析:根据“两点之间线段最短”可知:小鸟沿着两棵树的树梢进行直线飞行,所行的路程最短,运用勾股定理可将两点之间的距离求出.解答:解:如图,设大树高为AB=10m,小树高为CD=5m,过C点作CE⊥AB于E,则四边形EBDC是矩形,连接AC,∴EB=5m,EC=12m,AE=AB﹣EB=10﹣5=5(m),在Rt△AEC中,AC===13(m).故小鸟至少飞行13m.故选:C.点评:本题考查了勾股定理的应用,根据实际得出直角三角形,培养学生解决实际问题的能力.10.(2014秋•漳州期末)如图(1)所示在边长为a的正方形中挖掉一个边长为b的小正方形(a>b),把拿下的部分剪拼成一个矩形如图(2)所示,通过计算两个图形阴影部分的面积,验证了一个等式,则这个等式是()A.a2﹣b2=(a+b)(a﹣b)B.(a+b)2=a2+2ab+b2C.(a﹣b)2=a2﹣2ab+b2D.(a+2b)(a﹣b)=a2+ab﹣2b2考点:平方差公式的几何背景.分析:左图中阴影部分的面积=a2﹣b2,右图中矩形面积=(a+b)(a﹣b),根据二者相等,即可解答.解答:解:由题可得:a2﹣b2=(a﹣b)(a+b).故选:A.点评:此题主要考查了平方差公式的几何背景.解题的关键是运用阴影部分的面积相等得出关系式.11.(2014秋•漳州期末)如图,AE于BF交于点O,点O在CG上,根据尺规作图的痕迹,判断下列说法不正确的是()A.AE、BF是△ABC的内角平分线B.点O到△ABC三边的距离相等C.CG也是△ABC的一条内角平分线D.AO=BO=CO考点:作图—基本作图;角平分线的性质.分析:利用尺规作图的痕迹可得AE、BF是△ABC的内角平分线,即可得出答案.解答:解:∵由尺规作图的痕迹可得AE、BF是△ABC的内角平分线,∴点O到△ABC三边的距离相等,CG也是△ABC的一条内角平分线,故D选项不正确,故选:D.点评:本题主要考查了基本作图及角平分线的性质,解题的关键是熟记角平分线的作图方法.12.(2014秋•漳州期末)如图,已知S△ABC=12,AD平分∠BAC,且AD ⊥BD于点D,则S△ADC的值是()A.10 B.8 C. 6 D. 4考点:等腰三角形的判定与性质;三角形的面积.分析:延长BD交AC于点E,则可知△ABE为等腰三角形,则S△ABD=S△ADE,S△BDC=S△CDE,可得出S△ADC=S△ABC.解答:解:如图,延长BD交AC于点E,∵AD平分∠BAE,AD⊥BD,∴∠BAD=∠EAD,∠ADB=∠ADE,在△ABD和△AED中,,∴△ABD≌△AED(ASA),∴BD=DE,∴S△ABD=S△ADE,S△BDC=S△CDE,∴S△ABD+S△BDC=S△ADE+S△CDE=S△ADC,∴S△ADC═S△ABC=×12=6,故选C.点评:本题主要考查等腰三角形的判定和性质,由BD=DE得到S△ABD=S△ADE,S△BDC=S△CDE是解题的关键.二、填空题(共8小题,每小题3分,共24分)13.(3分)(2013•泰州)9的平方根是±3 .考点:平方根.专题:计算题.分析:直接利用平方根的定义计算即可.解答:解:∵±3的平方是9,∴9的平方根是±3.故答案为:±3.点评:此题主要考查了平方根的定义,要注意:一个非负数的平方根有两个,互为相反数,正值为算术平方根.14.(3分)(2014秋•漳州期末)计算(2m+n)(2m﹣n)= 4m2﹣n2.考点:平方差公式.专题:计算题.分析:原式利用平方差公式计算即可得到结果.解答:解:原式=4m2﹣n2.故答案为:4m2﹣n2.点评:此题考查了平方差公式,熟练掌握平方差公式是解本题的关键.15.(3分)(2014秋•漳州期末)计算:﹣8x3y2÷2xy= ﹣4x2y .考点:整式的除法.分析:利用系数,同底数幂分别相除后,作为商的因式求解.解答:解:﹣8x3y2÷2xy=﹣4x2y.故答案为:﹣4x2y.点评:本题主要考查了整式的除法,解题的关键是熟记,把系数同底数幂分别相除后,作为商的因式.16.(3分)(2014秋•漳州期末)若+(b﹣3)2=0,则a+b= 2 .考点:非负数的性质:算术平方根;非负数的性质:偶次方.分析:利用非负数的性质解得a,b,求得a+b.解答:解:∵+(b﹣3)2=0,≥0,(b﹣3)2≥0,∴a+1=0,b﹣3=0,解得:a=﹣1,b=3,∴a+b=2,故答案为:2.点评:本题主要考查了非负数的性质,利用算术平方根的非负性求值是解答此题的关键.17.(3分)(2014秋•漳州期末)测量某班40名学生的身高,得身高在1.60m以下的频率是0.4,则该班身高在1.60m以下的学生有16 人.考点:频数与频率.分析:利用频率=,进而得出该班身高在1.60m以下的学生数.解答:解:∵测量某班40名学生的身高,得身高在1.60m以下的频率是0.4,∴该班身高在1.60m以下的学生有:40×0.4=16(人).故答案为:16.点评:此题主要考查了频数与频率,正确掌握频数与频率之间的关系是解题关键.18.(3分)(2014秋•漳州期末)如图,∠A=∠D=90°,要使△ABC≌△DCB,只需再添加一个条件∠ABC=∠DCB,本题答案不唯一即可.考点:全等三角形的判定.专题:证明题;开放型.分析:添加的条件是∠ABC=∠DCB,根据全等三角形的判定定理AAS即可求出答案.解答:解:添加的条件是∠ABC=∠DCB,理由是:在△ABC和△DCB中∴△ABC≌△DCB(AAS),故答案为:∠ABC=∠DCB.本题答案不唯一.点评:本题主要考查对全等三角形的判定的理解和掌握,能熟练地根据全等三角形的判定定理进行证明是解此题的关键.19.(3分)(2014秋•漳州期末)如图,在Rt△ABC中,∠C=90°,AB的垂直平分线交AB于D,交BC于E,若CE=1,∠AEC=45°,则BE的长是.考点:线段垂直平分线的性质.分析:根据等腰直角三角形的性质得到AE=CE,然后根据线段的操作频繁的性质即可得到结果.解答:解:∵∠C=90°,∠AEC=45°,∴∠EAC=45°,∴AE=CE=,∵DE垂直平分AB,∴BE=AE=,故答案为:.点评:本题考查了线段垂直平分线上的点到线段两端点的距离相等的性质,等腰直角三角形的性质,熟记各性质是解题的关键.20.(3分)(2014秋•漳州期末)如图,在△ABC中,AB=AC=10,BC=12,若点P在边AC上移动,则BP的最小值是9.6 .考点:垂线段最短;等腰三角形的性质;勾股定理.分析:过点A作AE⊥BC,垂足为E,过点B作BD⊥AC,垂足为D,首先由等腰三角形三线合一可知BE=6,在Rt△AEB中,由勾股定理可求得AE=8,然后利用等面积法即可求得BD的长.解答:解:如图,过点A作AE⊥BC,垂足为E,过点B作BD⊥AC,垂足为D.∵AC=AC,AE⊥BC,∴BE=EC=6,在Rt△AEB中,==8,由三角形的面积公式可知:,即:,∴BD=9.6.故答案为:9.6.点评:本题主要考查的是等腰三角形的性质、勾股定理以及垂线段的性质,利用等面积法求得BD的长是解题的关键.三、解答题(共7题,满分52分)21.(6分)(2014秋•漳州期末)计算:++(﹣1)2015+|4﹣π|.(结果保留π)考点:实数的运算.专题:计算题.分析:原式第一项利用算术平方根定义计算,第二项利用立方根定义计算,第三项利用乘方的意义化简,最后一项利用绝对值的代数意义化简,计算即可得到结果.解答:解:原式=2+3﹣1+4﹣π=8﹣π.点评:此题考查了实数的运算,熟练掌握运算法则是解本题的关键.22.(8分)(2014秋•漳州期末)(1)9x2﹣4y2;(2)2x2+4x+2.考点:提公因式法与公式法的综合运用.专题:计算题.分析:(1)原式利用平方差公式分解即可;(2)原式提取2,再利用完全平方公式分解即可.解答:解:(1)原式=(3x+2y)(3x﹣2y);(2)原式=2(x2+2x+1)=2(x+1)2.点评:此题考查了提公因式法与公式法的综合运用,熟练掌握因式分解的方法是解本题的关键.23.(6分)(2014秋•漳州期末)如图,已知B,F,E,D在同一条直线上,AB=CD,AB∥CD,BF=DE,求证:AE=CF.考点:全等三角形的判定与性质.专题:证明题.分析:利用SAS证明△ABE≌△CDF,根据全等三角形,对应边相等,可得到结论AE=CF.解答:证明:∵BF=DE,∴BE+EF=DE+EF.即BE=DF,∵AB∥CD,∴∠B=∠D,在△ABE和△CDF中,,∴△ABE≌△CDF.∴AE=CF.点评:本题考查了全等三角形的判定和性质;证明线段相等往往可以通过全等三角形来证明,这是一种经常用、很重要的方法,要注意掌握.24.(6分)(2014秋•漳州期末)近年来,各地“广场舞”噪音干扰的问题倍受关注,某中学八年级学生就此问题对市民进行了随机问卷调查,问卷内容有以下四种:A.有一定影响,要控制好音量;B.影响很大,建议取缔;C.没影响;D.其它根据调查结果,制作了如图两幅不完整的统计图:根据以上信息解答下列问题:(1)本次调查的人数是200 人.(2)将两幅统计图补充完整.考点:条形统计图;扇形统计图.分析:(1)根据项目A有80人,所占的百分比是40%即可求得总人数;(2)根据百分比的意义即可求得B、C项目的人数以及B、D所占的百分比,从而补全图形.解答:解:(1)本次调查的总人数是:80÷40%=200(人),故答案是:200;(2)项目C的人数是:200×20%=40(人),B项目的人数是:200﹣80﹣40﹣50=30(人).D项目所占的百分比是:×100%=25%,B项目所占的百分比是:×100%=15%.点评:本题考查的是条形统计图的综合运用.读懂统计图,从统计图中得到必要的信息是解决问题的关键.条形统计图能清楚地表示出每个项目的数据.25.(8分)(2014秋•漳州期末)先化简,再求值:[(x﹣y)2]﹣x(x+y)+4xy÷y,其中x=﹣1,y=2.考点:整式的混合运算—化简求值.分析:先化简,再把x=﹣1,y=2代入求值.解答:解:[(x﹣y)2]﹣x(x+y)+4xy÷y=x2﹣2xy+y2﹣x2﹣xy+4x,=﹣3xy+y2+4x,当x=﹣1,y=2时,原式=6+4﹣4=6.点评:本题主要考查了整式的化简求值,解题的关键是正确的化简.26.(8分)(2014秋•漳州期末)如图,在海上观察所A处,我边防海警发现正北60海里的B处,有一可疑船只正在往正东方向80海里的C处行驶,速度为40海里/小时,我边防海警立即派海警船从A处出发,沿AC 方向行驶前往C处拦截,当可疑船只行驶到C处时,海警船也同时到达并将其截住,求海警船的速度.考点:勾股定理的应用.分析:首先利用勾股定理求得线段AC的长,然后利用行驶时间相等求得边防海警船的速度.解答:解:∵AB=60海里,BC=80海里,∴AC==100(海里),∵可疑船只的行驶速度为40海里/小时,∴可疑船只的行驶时间为80÷40=2(小时),∴我边防海警船的速度为100÷2=50(海里/小时),答:我边防海警船的速度为50海里/小时,才能恰好在C处将可疑船只截住.点评:本题考查了勾股定理在实际生活中的应用,本题中正确的找到CB,AB,AC的等量关系,并且根据该等量关系在直角△CAB中求解是解题的关键.27.(10分)(2014秋•漳州期末)如图,在Rt△ABC中,∠ACB=90°,BC=30cm,AC=40cm,点D在线段AB上从点B出发,以2cm/s的速度向终点A运动,设点D的运动时间为t0.(1)AB= 50 cm,AB边上的高为24 cm;(2)点D在运动过程中,当△BCD为等腰三角形时,求t的值.考点:勾股定理.专题:动点型.分析:(1)在Rt△ABC中,由勾股定理即可求出AB;由直角三角形的面积即可求出斜边上的高;(2)分三种情况:①当BD=BC=30cm时,得出2t=30,即可得出结果;②当CD=CB=30cm时,作CE⊥AB于E,则BE=DE=BD=t,由(1)得出CE=24,由勾股定理求出BE,即可得出结果;③当DB=DC时,∠BCD=∠B,证明DA=DC,得出AD=DB=AB,即可得出结果.解答:解:(1)∵在Rt△ABC中,∠ACB=90°,BC=30cm,AC=40cm,∴AB===50(cm);作AB边上的高CE,如图1所示:∵Rt△ABC的面积=AB•CE=AC•BC,∴CE===24(cm);故答案为:50,24;(2)分三种情况:①当BD=BC=30cm时,2t=30,∴t=15(s);②当CD=CB=30cm时,作CE⊥AB于E,如图2所示:则BE=DE=BD=t,由(1)得:CE=24,在Rt△BCE中,由勾股定理得:BE===18(cm),∴t=18s;③当DB=DC时,∠BCD=∠B,∵∠A=90°﹣∠B,∠ACD=90°﹣∠BCD,∴∠ACD=∠A,∴DA=DC,∴AD=DB=AB=25(cm),∴2t=25,∴t=12.5(s);综上所述:t的值为15s或18s或12.5s.点评:本题考查了勾股定理、等腰三角形的判定与性质、三角形面积的计算;本题综合性强,有一定难度,特别是(2)中,需要进行分类讨论,运用勾股定理和等腰三角形的性质才能得出结果.。
广州市荔湾区八年级上期末质量数学试题(有答案)-精华版
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广东省广州市荔湾区2017-2018 学年八年级上期末质量检测数学试题一、选择题(本大题共10 小题,每小题2 分,共20 分)1.在①角、②等边三角形、③平行四边形、④梯形中是轴对称图形的是()A.①②B.③④C.②③D.②④【分析】根据轴对称图形的概念:如果一个图形沿一条直线折叠,直线两旁的部分能够互相重合,这个图形叫做轴对称图形,这条直线叫做对称轴可得到轴对称图形,再根据对称轴的条数进行进一步筛选可得答案.解:①角、②等边三角形、③平行四边形、④梯形中是轴对称图形的是①②,故选:A.【点评】此题主要考查了轴对称图形,关键是找到图形的对称轴.2.计算4x2•x3的结果是()A.4x6 B.4x5 C.x6 D.x5【分析】根据单项式与单项式相乘,把他们的系数分别相乘,相同字母的幂分别相加,其余字母连同他的指数不变,作为积的因式,计算即可.解:4x2•x3=4x5.故选:B.【点评】本题考查了单项式与单项式相乘,熟练掌握运算法则是解题的关键.3.若x,y的值均扩大为原来的2 倍,则下列分式的值保持不变的是()A.B.C.D.【分析】根据分式的基本性质即可求出答案.解:A、原式=,与原来的分式的值不同,故本选项错误;B、原式=,与原来的分式的值不同,故本选项错误;C、原式=,与原来的分式的值不同,故本选项错误;D、原式==,与原来的分式的值相同,故本选项正确.故选:D.【点评】本题考查分式的基本性质,解题的关键是熟练运用分式的基本性质,本题属于基础题型.4.下列计算中,正确的是()A.2a3÷a3=6 B.(a﹣b)2=﹣a2﹣b2C.2a6÷a2=a3D.(﹣ab)2=a2b2【分析】根据各个选项中的式子可以计算出正确的结果,从而可以解答本题.解:∵2a3÷a3=2,故选项A 错误,∵(a﹣b)2=a2﹣2ab+b2,故选项B 错误,∵2a6÷a2=a4,故选项C 错误,∵(﹣ab)2=a2b2,故选项D 正确,故选:D.【点评】本题考查整式的混合运算,解答本题的关键是明确整式的混合运算的计算方法.5.长度分别为2,7,x的三条线段能组成一个三角形,x的值可以是()A.4 B.5 C.6 D.9【分析】已知三角形的两边长分别为2 和7,根据在三角形中任意两边之和>第三边,任意两边之差<第三边;即可求第三边长的范围,再结合选项选择符合条件的.解:由三角形三边关系定理得7﹣2<x<7+2,即5<x<9.因此,本题的第三边应满足5<x<9,把各项代入不等式符合的即为答案.4,5,9 都不符合不等式5<x<9,只有6 符合不等式,故选:C.【点评】考查了三角形三边关系,此类求三角形第三边的范围的题,实际上就是根据三角形三边关系定理列出不等式,然后解不等式即可.6.内角和等于外角和的多边形是()A.三角形B.四边形C.五边形D.六边形【分析】多边形的内角和可以表示成(n﹣2)•180°,外角和是固定的360°,从而可根据外角和等于内角和列方程求解.解:设所求n 边形边数为n,则360°=(n﹣2)•180°,解得n=4.∴外角和等于内角和的多边形是四边形.故选:B.【点评】本题主要考查了多边形的内角和与外角和、方程的思想,关键是记住内角和的公式与外角和的特征,比较简单.7.如图,点P是∠AOB 平分线IC上一点,PD⊥OB,垂足为D,若PD=3,则点P到边OA的距离是()A.B.2 C.3 D.4【分析】作PE⊥OA 于E,根据角平分线的性质解答.解:作PE⊥OA 于E,∵点P 是∠AOB 平分线OC 上一点,PD⊥OB,PE⊥ OA,∴PE=PD=3,故选:C.【点评】本题考查的是角平分线的性质,掌握角的平分线上的点到角的两边的距离相等是解题的关键.8.如图,△AOC≌△BOD,点A与点B是对应点,那么下列结论中错误的是()A.AB=CD B.AC=BD C.AO=BO D.∠A=∠B【分析】根据全等三角形的对应边、对应角相等,可得出正确的结论,可得出答案.解:∵△AOC≌△BOD,∴∠A=∠B,AO=BO,AC=BD,∴B、C、D 均正确,而AB、CD 不是不是对应边,且CO≠AO,∴AB≠CD,故选:A.【点评】本题主要考查全等三角形的性质,掌握全等三角形的对应边、角相等是解题的关键.9.如图,在△ABC中,∠B=30°,BC的垂直平分线交AB于E,垂足为D,如果ED=5,则EC 的长为()A.5 B.8 C.9 D.10【分析】先根据线段垂直平分线的性质得出BE=CE,故可得出∠B=∠DCE,再由直角三角形的性质即可得出结论.解:∵在△ABC 中,∠B=30°,BC 的垂直平分线交AB 于E,ED=5,∴BE=CE,∴∠B=∠DCE=30°,在Rt△CDE 中,∵∠DCE=30°,ED=5,∴CE=2DE=10.故选:D.【点评】本题考查的是线段垂直平分线的性质,熟知线段垂直平分线上任意一点,到线段两端点的距离相等是解答此题的关键.10.如图,AD是△ABC的中线,E,F分别是AD和AD延长线上的点,且DE=DF,连接BF,CE,下列说法:①△ABD 和△ACD 面积相等;②∠BAD=∠CAD;③△BDF≌△CDE;④BF∥CE;⑤CE=AE.其中正确的是()A.①②B.③⑤C.①③④D.①④⑤【分析】根据三角形中线的定义可得BD=CD,根据等底等高的三角形的面积相等判断出①正确,然后利用“边角边”证明△BDF 和△CDE 全等,根据全等三角形对应边相等可得CE=BF,全等三角形对应角相等可得∠F=∠CED,再根据内错角相等,两直线平行可得BF∥CE.解:∵AD 是△ABC 的中线,∴BD=CD,∴△ABD 和△ACD 面积相等,故①正确;∵AD 为△ABC 的中线,∴BD=CD,∠BAD 和∠CAD 不一定相等,故②错误;在△BDF 和△CDE 中,,∴△BDF≌△CDE(SAS),故③正确;∴∠F=∠DEC,∴BF∥CE,故④正确;∵△BDF≌△CDE,∴CE=BF,故⑤错误,正确的结论为:①③④,故选:C.【点评】本题考查了全等三角形的判定与性质,等底等高的三角形的面积相等,熟练掌握三角形全等的判定方法并准确识图是解题的关键.二、填空题(本大题共6 小题,每小题3 分,共18 分)11.(3 分)计算:40+2﹣1= 1 .【分析】直接利用零指数幂的性质以及负指数幂的性质分别化简得出答案.解:∵40+2﹣1=1+=1.故答案为:1.【点评】此题主要考查了零指数幂的性质以及负指数幂的性质,正确化简各数是解题关键.12.(3 分)要使分式有意义,则x的取值范围为x≠﹣3 .【分析】根据分式有意义,分母不等于0 列不等式求解即可.解:由题意得,x+3≠0,解得x≠﹣3.故答案为:x≠﹣3.【点评】本题考查了分式有意义的条件,从以下三个方面透彻理解分式的概念:(1)分式无意义⇔分母为零;(2)分式有意义⇔分母不为零;(3)分式值为零⇔分子为零且分母不为零.13.(3 分)若x2﹣2ax+16 是完全平方式,则a=±4.【分析】完全平方公式:(a±b)2=a2±2ab+b2,这里首末两项是x 和4 这两个数的平方,那么中间一项为加上或减去x 和4 积的2 倍.解:∵x2﹣2ax+16 是完全平方式,∴﹣2ax=±2×x×4∴a=±4.【点评】本题是完全平方公式的应用,两数的平方和,再加上或减去它们积的2倍,就构成了一个完全平方式.注意积的2 倍的符号,避免漏解.14.(3 分)若一个等腰三角形的周长为26,一边长为6,则它的腰长为 10 .【分析】题中给出了周长和一边长,而没有指明这边是否为腰长,则应该分两种情况进行分析求解.解:①当6 为腰长时,则腰长为6,底边=26﹣6﹣6=14,因为14>6+6,所以不能构成三角形;②当6 为底边时,则腰长=(26﹣6)÷2=10,因为6﹣6<10<6+6,所以能构成三角形;故腰长为10.故答案为:10.【点评】此题主要考查等腰三角形的性质及三角形三边关系的综合运用,关键是利用三角形三边关系进行检验.15.(3 分)如图,在△ABC 中,CD,BE分别是AB,AC 边上的高,且CD,BE相交于点P,若∠A=70°,则∠BPC=110 °.【分析】根据四边形的内角和等于360°,求出∠DPE 的度数,再根据对顶角相等解答.解:∵CD、BE 分别是AB、AC 边上的高,∴∠DPE=360°﹣90°×2﹣70°=110°,∴∠BPC=∠DPE=110°.故答案为:110°.【点评】本题考查了多边形的内角和,对顶角相等的性质,熟记定理并准确识图理清图中各角度之间的关系是解题的关键.16.(3 分)如图,在锐角三角形ABC 中,AC=6,△ABC 的面积为15,∠BAC的平分线交BC 于点D,M,N 分别是AD 和AB 上的动点,则BM+MN 的最小值是5 .【分析】如图,作N 关于AD 的对称点N′,连接MN′,作BN″⊥AC 于N″ 交AD 于M′.因为BM+MN=BM+MN′≤BN″,所以当M 与M′,N 与N″重合时,BN″最小,求出BN″即可解决问题.解:如图,作N 关于AD 的对称点N′,连接MN′,作BN″⊥AC 于N″交AD于M′.∵BM+MN=BM+MN′≤BN″,∴当M 与M′,N 与N″重合时,BN″最小,∵×AC×BN″=15,AC=6,∴BN″=5,∴BM+MN 的最小值为5,故答案为:5.【点评】本题考查轴对称﹣最短问题、垂线段最短等知识,解题的关键是重合利用对称,垂线段最短解决最值问题,属于中考常考题型.三、解答题(本大题共7 题,共62 分,解答应写出文字说明.17.(8 分)计算:(1)(x+2)(2x﹣1)(2)(﹣2x3)2﹣3x2(x4﹣y2)【分析】(1)根据多项式的乘法解答即可;(2)根据整式的混合计算解答即可.解:(1)原式=2x2﹣x+4x﹣2=2x2+3x﹣2;(2)原式=4x6﹣3x6+3x2y2=x6+3x2y2.【点评】此题考查整式的混合计算,关键是根据整式的混合计算顺序和法则解答.18.(8 分)分解因式:(1)2a2﹣8(2)(x﹣1)2﹣2(x﹣1)﹣3【分析】(1)原式提取公因式,再利用平方差公式分解即可;(2)原式利用十字相乘法分解即可.解:(1)原式=2(a2﹣4)=2(a+2)(a﹣2);(2)原式=(x﹣1﹣3)(x﹣1+1)=x(x﹣4).【点评】此题考查了因式分解﹣十字相乘法,以及提公因式法与公式法的综合运用,熟练掌握因式分解的方法是解本题的关键.19.(8 分)计算:(1)+(2)•(1+)【分析】(1)先通分,再根据同分母分式的加法法则计算可得;(2)先利用乘法分配律展开计算,再进一步计算可得.解:(1)原式=+=;(2)原式=+•=+1=+=.【点评】本题主要考查分式的混合运算,解题的关键是熟练掌握分式的混合运算顺序和运算法则.20.(8 分)如图,平面直角坐标系中,△ABC 的三个顶点坐标分别为A(1,3),B(3,3),C(4,﹣1).(1)画出△ABC 关于x 轴对称的△A1B1C1,写出点A1,B1,C1的坐标;(2)求△A1B1C1的面积.【分析】(1)分别作出点A、B、C 关于x 轴的对称点,再顺次连接可得;(2)结合图形,利用三角形的面积公式计算可得.解:(1)如图所示,△A1B1C1即为所求,其中A1的坐标为(1,﹣3),B1的坐标为(3,﹣3),C1的坐标为(4,1);(2)△A1B1C1的面积为×2×4=4.【点评】本题主要考查作图﹣轴对称变换,解题的关键是掌握轴对称变换的定义和性质及三角形的面积公式.21.(10 分)如图,AE⊥DB,CF⊥DB,垂足分别是点E,F,DE=BF,AE=CF,求证:∠A=∠C.【分析】欲证明∠A=∠C,只要证明△AEB≌△CFD 即可.证明∵AE⊥BD,CF⊥BD,∴∠AEB=∠DFC=90°,∵DE=BF,∴DF=BE,在△AEB 和△CFD 中,,△AEB≌△CFD(SAS),∴∠A=∠C.【点评】本题考查全等三角形的判定和性质、平行线的性质和判定等知识,解题的关键是熟练掌握全等三角形的判定方法,属于中考常考题型.22.(10 分)某美术社团为练习素描需要购买素描本,第一次用600 元购买了若干本素描本,用完后再花了1200 元继续在同一家商店购买同样分素描本,但这次的单价是第一次单价的1.2 倍,购买的数量比第一次多了40 本,求第一次的素描本单价是多少元?【分析】设第一次的素描本单价是x 元,根据结果比上次多买了40 本列出方程解答即可解:设第一次的素描本单价是x 元,依题意得:﹣=40 解得x=10经检验x=10 是原方程的解答:第一次的素描本单价是10 元.【点评】本题考查了分式方程的应用,解答本题的关键是读懂题意,设出未知数,找出合适的等量关系,列方程解答即可.23.(10 分)如图,在等腰Rt△ABC 中,角ACB=90°,P是线段BC 上一动点(与点B,C 不重合)连接AP,延长BC 至点Q,使CQ=CP,过点Q 作QH⊥AP 于点H,交AB 于点M.(1)∠APC=α,求∠AMQ的大小(用含α的式子表示);(2)在(1)的条件下,过点M作ME⊥QB于点E,试证明PC与ME之间的数量关系,并证明.【分析】(1)由等腰直角三角形的性质得出∠BAC=∠B=45°,∠PAB=45°﹣α,由直角三角形的性质即可得出结论;(2)由AAS 证明△APC≌△QME,得出PC=ME,解:(1)∠AMQ=45°+α;理由如下:∵∠PAC=α,△ACB 是等腰直角三角形,∴∠BAC=∠B=45°,∠PAB=45°﹣α,∵QH⊥AP,∴∠AHM=90°,∴∠AMQ=180°﹣∠AHM﹣∠PAB=45°+α;(2)结论:PC=ME.理由:连接AQ,作ME⊥QB,如图所示:∵AC⊥QP,CQ=CP,∴∠QAC=∠PAC=α,∴∠QAM=45°+α=∠AMQ,∴AP=AQ=QM,在△APC 和△QME 中,,∴△APC≌△QME(AAS),∴PC=ME,【点评】本题考查了全等三角形的判定与性质、等腰直角三角形的判定与性质、勾股定理;熟练掌握等腰直角三角形的判定与性质,证明三角形全等是解决问题的关键.。
2013-2014学年广东省广州市荔湾区八年级(上)期末数学试卷
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2013-2014学年广东省广州市荔湾区八年级(上)期末数学试卷一、选择题(共10小题,每小题2分,满分20分)1.(2013荔湾区期末)下列计算正确的是()A.x•x4=x4B.x+x3=x4C.x•x4=x5D.x4+x4=x82.(2013荔湾区期末)要使x2+6x+k是完全平方式,那么k的值是()A.9 B.12 C.±9 D.363.(2013荔湾区期末)下列四个分式中,是最简分式的为()A. B.C. D.4.(2013荔湾区期末)下列变形中,一定正确的是()A.B.C.D.5.(2013荔湾区期末)如图,在△ABC中,∠C=90°,∠BAC的平分线交BC于D,且DC=8cm,则点D 到AB的距离是()cm.A.16 B.8 C.6 D.46.(2013荔湾区期末)如果两个图形是全等图形,那么下列判断不正确的是()A.形状相同 B.大小相同C.面积相等 D.周长不一定相等7.(2013荔湾区期末)点D是△ABC中AB边上的一点,线段CD把△ABC分成面积相等的两部分,下面说法正确的是()A.CD是△ABC的高 B.CD是△ABC的角平分线C.CD是△ABC的中线D.以上都不正确8.(2013荔湾区期末)如果一个多边形的内角和是外角和的5倍,那么这个多边形的边数是()A.12 B.11 C.10 D.99.(2013荔湾区期末)下列判断正确的是()A.点(﹣3,4)与(3,4)关于x轴对称B.点(3,﹣4)与点(﹣3,4)关于y轴对称C.点(3,4)与点(3,﹣4)关于x轴对称D.点(4,﹣3)与点(4,3)关于y轴对称10.(2013荔湾区期末)△ABC中,AB=AC=8,∠BAC=120°,则边BC上的高AD长为()A.2 B.4 C.6 D.8二、填空题(共6小题,每小题3分,满分18分)11.(2013荔湾区期末)用科学记数法表示0.0000031=.12.(2013荔湾区期末)计算:(﹣2a2)3=.13.(2013荔湾区期末)计算:(﹣a2+a)÷a=.14.(2013荔湾区期末)如图,△AEB≌△DFC,AE⊥CB,DF⊥BC,AE=DF,∠C=28°,则∠A=.15.(2013荔湾区期末)等腰三角形两条边长分别为8cm和6cm,则这个三角形的周长是cm.16.(2013荔湾区期末)如图,已知线段段AB的两个端点A、B正好关于直线CD对称,且线段AB与直线CD相交于点O,若AO=4厘米,AC=6厘米,则△ABC的周长为厘米.三、解答题17.(2013荔湾区期末)如图,已知四边形ABCD和直线l,试在图形中作四边形A′B′C′D′,使四边形A′B′C′D′和四边形ABCD关于直线l对称.(不要求写作法,只仅留作图痕迹)18.(2013荔湾区期末)计算:(1)(2x﹣3)(x﹣5);(2)(a2﹣b3)(a2+b3)19.(2013荔湾区期末)分解因式:(1)﹣5a3b+20ab3;(2)(3x﹣2)2﹣2(3x﹣2)+1.20.(2013荔湾区期末)计算:(1)+;(2)+﹣.21.(2013荔湾区期末)甲、乙两班学生植树,原计划6天完成任务,他们共同劳动4天后,乙班另有任务调走,甲班又用6天种完.求甲、乙两班单独完成各需多少天?22.(2013荔湾区期末)如图,已知∠A=∠D=90°,AC=BD,求证:(1)AB=DC;(2)OB=OC.23.(2013荔湾区期末)如图,△ABC中,∠BAC=∠BCA,CD平分∠ACB,CE⊥AB交AB的延长线于点E,若∠DCE=54°,求∠A的度数.24.(2013荔湾区期末)如图,在△ABC中,∠B=60°,AD、CE分别是∠BAC、∠BCA的平分线,AD、CE相交于点F,请你判断并写出FE与FD之间的数量关系;请说明理由.2013-2014学年广东省广州市荔湾区八年级(上)期末数学试卷参考答案与试题解析一、选择题(共10小题,每小题2分,满分20分)1.(2分)(2013秋•荔湾区期末)下列计算正确的是()A.x•x4=x4B.x+x3=x4C.x•x4=x5D.x4+x4=x8【解答】解:A、底数不变指数相加,故A错误;B、不是同底数幂的乘法,指数不能相加,故B错误;C、底数不变指数相加,故C正确;D、系数相加字母部分不变,故D错误;故选:C.2.(2分)(2015秋•封开县期末)要使x2+6x+k是完全平方式,那么k的值是()A.9 B.12 C.±9 D.36【解答】解:∵x2+6x+k=x2+2•3•x+k,∴k=32=9.故选A.3.(2分)(2013秋•荔湾区期末)下列四个分式中,是最简分式的为()A. B.C. D.【解答】解:A、=;B、=x+1;C、=a+b;D、的分子、分母都不能再分解,且不能约分,是最简分式;故选D.4.(2分)(2013秋•荔湾区期末)下列变形中,一定正确的是()A.B.C.D.【解答】解:A、分子、分母同时减去3,值不一定不变.例如:当x=3,y=4时,原式不成立;故本选项错误;B、当m=0时,该等式不成立;故本选项错误;C、当x=0时,该等式不成立;故本选项错误;D、分式的分子、分母同时乘以不为0的y(分母不为0),分式的值不变.故本选项正确.故选D.5.(2分)(2013秋•荔湾区期末)如图,在△ABC中,∠C=90°,∠BAC的平分线交BC于D,且DC=8cm,则点D到AB的距离是()cm.A.16 B.8 C.6 D.4【解答】解:如图,过点D作DE⊥AB于E,∵AD是∠BAC的平分线,∠C=90°,∴DE=CD=8cm,即点D到AB的距离是8cm.故选B.6.(2分)(2013秋•荔湾区期末)如果两个图形是全等图形,那么下列判断不正确的是()A.形状相同 B.大小相同C.面积相等 D.周长不一定相等【解答】解:根据全等图形的定义可得如果两个图形是全等图形,那么它的形状、大小、面积、周长都相等,因此D说法错误,故选:D.7.(2分)(2013秋•荔湾区期末)点D是△ABC中AB边上的一点,线段CD把△ABC分成面积相等的两部分,下面说法正确的是()A.CD是△ABC的高 B.CD是△ABC的角平分线C.CD是△ABC的中线D.以上都不正确【解答】解:∵线段CD将△ABC分为面积相等的两部分,△ACD与△BCD的高线是同一条线段,∴△ACD与△BCD应该是等底同高的两个三角形,即AD=BD,∴线段CD是△ABC的一条中线.故选:C.8.(2分)(2013秋•荔湾区期末)如果一个多边形的内角和是外角和的5倍,那么这个多边形的边数是()A.12 B.11 C.10 D.9【解答】解:设这个多边形是n边形,根据题意得,(n﹣2)•180°=5×360°,解得n=12.故选A.9.(2分)(2013秋•荔湾区期末)下列判断正确的是()A.点(﹣3,4)与(3,4)关于x轴对称B.点(3,﹣4)与点(﹣3,4)关于y轴对称C.点(3,4)与点(3,﹣4)关于x轴对称D.点(4,﹣3)与点(4,3)关于y轴对称【解答】解:A、点(﹣3,4)与(3,4)关于y轴对称;B、点(3,﹣4)与点(﹣3,4)关于原点对称;C、点(3,4)与点(3,﹣4)关于x轴对称;D、点(4,﹣3)与点(4,3)关于x轴对称.故选C.10.(2分)(2013秋•荔湾区期末)△ABC中,AB=AC=8,∠BAC=120°,则边BC上的高AD长为()A.2 B.4 C.6 D.8【解答】解:∵AB=AC,∠BAC=120°,∴∠B=(180°﹣120°)=30°,∴BC上的高AD=AB=×8=4.故选B.二、填空题(共6小题,每小题3分,满分18分)11.(3分)(2013秋•荔湾区期末)用科学记数法表示0.0000031= 3.1×10﹣6.【解答】解:0.000 0031=3.1×10﹣6;故答案为:3.1×10﹣6.12.(3分)(2013•椒江区二模)计算:(﹣2a2)3=﹣8a6.【解答】解:(﹣2a2)3=(﹣2)3(a2)3=﹣8a6.故答案为:﹣8a6.13.(3分)(2013秋•荔湾区期末)计算:(﹣a2+a)÷a=﹣a+1.【解答】解:原式=﹣a+1.故答案为:﹣a+114.(3分)(2013秋•荔湾区期末)如图,△AEB≌△DFC,AE⊥CB,DF⊥BC,AE=DF,∠C=28°,则∠A=62°.【解答】解:∵DF⊥BC,∠C=28°,∴∠D=90°﹣28°=62°,∵△AEB≌△DFC,∴∠A=∠D=62°.故答案为:62°.15.(3分)(2013秋•荔湾区期末)等腰三角形两条边长分别为8cm和6cm,则这个三角形的周长是22或20cm.【解答】解:根据题意,①当腰长为8cm时,周长=8+8+6=22(cm);②当腰长为6cm时,周长=6+6+8=20(cm);故答案为:22或20.16.(3分)(2013秋•荔湾区期末)如图,已知线段段AB的两个端点A、B正好关于直线CD对称,且线段AB与直线CD相交于点O,若AO=4厘米,AC=6厘米,则△ABC的周长为20厘米.【解答】解:∵线段AB的两个端点A、B正好关于直线CD对称,且线段AB与直线CD相交于点O,∴AO=BO,AC=BC,∵AO=4厘米,AC=6厘米,∴△ABC的周长为4×2+6×2=20厘米,故答案为:20.三、解答题17.(6分)(2013秋•荔湾区期末)如图,已知四边形ABCD和直线l,试在图形中作四边形A′B′C′D′,使四边形A′B′C′D′和四边形ABCD关于直线l对称.(不要求写作法,只仅留作图痕迹)【解答】解:如图所示,四边形A′B′C′D'即为四边形ABCD关于直线l对称的图形:.18.(6分)(2013秋•荔湾区期末)计算:(1)(2x﹣3)(x﹣5);(2)(a2﹣b3)(a2+b3)【解答】解:(1)(2x﹣3)(x﹣5)=2x2﹣10x﹣3x+15=2x2﹣13x+15;(2)(a2﹣b3)(a2+b3)=a4﹣b6.19.(8分)(2013秋•荔湾区期末)分解因式:(1)﹣5a3b+20ab3;(2)(3x﹣2)2﹣2(3x﹣2)+1.【解答】解:(1)原式=﹣5ab(a2﹣4b2)=﹣5ab(a+2b)(a﹣2b);(2)原式=(3x﹣2﹣1)2=(3x﹣3)2=9(x﹣1)2.20.(8分)(2013秋•荔湾区期末)计算:(1)+;(2)+﹣.【解答】解:(1)原式=1+=;(2)原式=+==.21.(8分)(2013秋•荔湾区期末)甲、乙两班学生植树,原计划6天完成任务,他们共同劳动4天后,乙班另有任务调走,甲班又用6天种完.求甲、乙两班单独完成各需多少天?【解答】解:设甲班单独完成此项工作需要x天,根据题意得:+=1解得:x=18经检验x=18是原方程的根.∵两队合作6天完成任务,∴设乙队单独完成需要y天,则=.∴乙队单独完成需要9天答:甲队单独需要18天完成,乙对单独需要9天完成.22.(8分)(2013秋•荔湾区期末)如图,已知∠A=∠D=90°,AC=BD,求证:(1)AB=DC;(2)OB=OC.【解答】证明:(1)∵∠A=∠D=90°,∴△ABC和△DCB是直角三角形.在Rt△ABC和Rt△DCB中∴Rt△ABC≌Rt△DCB(HL),∴AB=DC;(2)∵△ABC≌△DCB,∴∠ACB=∠DBC,∴OB=OC.23.(8分)(2013秋•荔湾区期末)如图,△ABC中,∠BAC=∠BCA,CD平分∠ACB,CE⊥AB交AB 的延长线于点E,若∠DCE=54°,求∠A的度数.【解答】解:∵CD平分∠ACB,∴∠ACD=∠BCA=∠A,∵CE⊥AB,∴∠A+∠ACD+∠DCE=90°,∴∠A+∠A+54°=90°,解得∠A=24°.24.(10分)(2013秋•荔湾区期末)如图,在△ABC中,∠B=60°,AD、CE分别是∠BAC、∠BCA的平分线,AD、CE相交于点F,请你判断并写出FE与FD之间的数量关系;请说明理由.【解答】解:FE=FD.理由如下:方法一:如图1,在AC上截取AG=AE,连接FG,∵AD是∠BAC的平分线,∴∠1=∠2,在△AEF和△AGF中,,∴△AEF≌△AGF(SAS),∴∠AFE=∠AFG,FE=FG,∵∠B=60°,∴∠BAC+∠ACB=180°﹣60°=120°,∵AD、CE分别是∠BAC、∠BCA的平分线,∴∠2=∠BAC,∠3=∠ACB,∴∠2+∠3=(∠BAC+∠ACB)=×120°=60°,∴∠AFE=∠CFD=∠AFG=60°.∴∠CFG=180°﹣∠AFG﹣∠CFD=180°﹣60°﹣60°=60°,∴∠CFG=∠CFD,∵CE是∠BCA的平分线,∴∠3=∠4,在△CFG和△CFD中,,∴△CFG≌△CFD(ASA),∴FG=FD,∴FE=FD;方法二:如图2,过点F分别作FG⊥AB于点G,FH⊥BC于点H,∵F是△ABC的内心,∴FG=FH,∵∠B=60°,∴∠BAC+∠ACB=180°﹣60°=120°,∵AD、CE分别是∠BAC、∠BCA的平分线,∴∠2=∠BAC,∠3=∠ACB,∴∠2+∠3=(∠BAC+∠ACB)=×120°=60°,∴∠AFE=∠2+∠3=60°,∴∠GEF=60°+∠1,又∵∠HDF=∠B+∠1=60°+∠1,∴∠GEF=∠HDF,在△EGF和△DHF中,,∴△EGF≌△DHF(AAS),∴FE=FD.参与本试卷答题和审题的老师有:2300680618;星期八;HJJ;nhx600;sd2011;zhjh;蓝月梦;gbl210;zjx111;sks;sjzx;caicl;wdzyzlhx;hdq123(排名不分先后)菁优网2016年11月14日。
2015-2016学年第一学期荔湾区期末初三统考试卷数学科附答案
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2015-2016学年第一学期荔湾区期末初三统考试卷数学科 第一部分 选择题(共30分)一、 选择题(本题共有10小题,每小题3分,共30分.在每小题给出的四个选项中,只有一项是符合题目要求的.)1、不解方程,判别一元二次方程2261x x -=的根的情况是 ( )A .有两个不相等的实数根B .没有实数根C .有两个相等的实数根D .无法确定2、如图,是一个装饰物品连续旋转闪烁所成的三个图形,照此规律闪烁,下一个呈现出来的图形是 ( )3、从标号分别为1,2,3,4,5的5 张卡片中,随机抽取1张,下列事件中,必然事件是 ( )A .标号小于 6B .标号大于 6C .标号是奇数D .标号是34、将抛物线23y x = 向上平移 2 个单位,得到抛物线的解析式是 ( )A .23y x =-2B .23y x =C .23(2)y x =+D .23y x =+25、 2012-2013NBA 整个常规赛季中,科比罚球投篮的命中率大约是83.3%.下列对科比罚球投篮的说法错误的是 ( )A .罚球投篮 2 次,一定全部命中B .罚球投篮 2 次,不一定全部命中C .罚球投篮1次,命中的可能性比较大D .罚球投篮1次,不命中的可能性较小6、如图是二次函数224y x x =-++的图象,使 y ≤4 成立的 x 的取值范围是 ( )7、数学课上,老师让同学们观察如图所示的图形,问:它绕着圆心O 旋转多少度后和它自身重合?甲同学说: 45°;乙同学说: 60°;丙同学说:90°;丁同学说:135°.以上四位同学的回答中,错误的是 ( )A .甲B .乙C .丙D .丁8、如图,在圆O 中,OC ⊥弦 AB 于点C ,AB =4,OC =1,则OB 的长是 ( )A . 3B . 5C . 15D . 179、如图,AB 是圆O 的直径, B C ,CD ,DA 是圆O 的弦,且 BC =CD =DA ,则∠BCD 等于 ( )A . 100°B . 110°C . 120°D . 135°10、如图,反比例函数(0)k y x x=> 的图象经过矩形OABC 对角线的交点 M ,分别与 AB ,BC 相交于点 D ,E ,若四边形ODBE 的面积为 6 ,则 k 的值为 ( )A . 4B . 3C . 2D . 1第二部分 非选择题(共120分)二、填空题(本大题共有6小题,每小题3分,共18分)11、设一元二次方程2830x x --=的两个实数根分别为1x 和2x ,则1x +2x = ______ 12、二次函数225y x x =+-的顶点坐标是 ______ .13、已知一个函数的图象与6y x=的图象关于 y 轴成轴对称,则该函数的解析式为 ______ . 14、有两把不同的锁和三把钥匙,其中两把钥匙能打开同一把锁,第三把钥匙能打开另一把锁,任意取出一把钥匙去开任意一把锁,一次能打开锁的概率是 ______ .15、如图,点A ,B ,C ,D 分别是圆O 上四点,∠ABD =20°, BD 是直径,那么 ∠ACB = ______16、如图,△ABC 和△A 'B ' C 是两个完全重合的直角三角板,∠B =30°,斜边长为10cm .三角板 A ' B ' C 绕直角顶点C 顺时针旋转,当点 A ' 落在 AB 边上时, CA ' 旋转所构成的扇形的弧长为 ______ cm .三、解答题(本大题共9小题,共 102分.解答应写出文字说明、证明过程或演算步骤.)。
广东省广州市荔湾区八年级上学期数学期末试卷附答案
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∴DE+DF=AD.故②符合题意. ③由题意可知:∠EDA=∠ADF=60°. 假设 MD 平分∠ADF,则∠ADM=30°.则∠EDM=90°, 又∵∠E=∠BMD=90°, ∴∠EBM=90°. ∴∠ABC=90°. ∵∠ABC 是否等于 90°不知道, ∴不能判定 MD 平分∠EDF.故③不符合题意. ④∵DM 是 BC 的垂直平分线, ∴DB=DC. 在 Rt△BED 和 Rt△CFD 中
故答案为:D. 【分析】根据三角形任意两边之和大于第三边,任意两边之差小于第三边可得出答案.在运用三角形三边 关系判定三条线段能否构成三角形时,只要两条较短的线段长度之和大于第三条线段的长度即可判定这三 条线段能构成一个三角形. 7.【解析】【解答】解: ∵△ABE≌△ACF, ∴AC=AB=5, ∴EC=AC-AE=5-2=3. 故答案为:B. 【分析】根据全等三角形对应边相等得 AC 的长,结合 AE=2,从而求出 EC 的长. 8.【解析】【解答】解:∵△ABC 是等腰三角形,底边 BC=5,周长为 21, ∴AC=AB=8, 又∵DE 是 AB 的垂直平分线, ∴AE=BE , ∴△BEC 的周长=BE+CE+CB=AE+CE+BC=AC+CB=13, ∴△BEC 的周长为 13. 故答案为:A . 【分析】由于△ABC 是等腰三角形,底边 BC=5,周长为 21,由此求出 AC=AB=8,又 DE 是 AB 的垂直平 分线,根据线段的垂直平分线的性质得到 AE=BE , 由此得到△BEC 的周长=BE+CE+CB=AE+CE+BC= AC+CB , 然后利用已知条件即可求出结果. 9.【解析】【解答】解:∵在△ABC 中,OB 和 OC 分别平分∠ABC 和∠ACB,
2014---2015学年广州市荔湾区初二上学期期末英语试卷及答案(区统考)
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2014-2015学年第一学期期末教学质量检测八年级英语(荔湾区)听力略二、语言知识与运用(15分)第一节单项填空(共10小题,每小题1分,满分10分)16. Would you like to drink coffee, Jane?I want a cup of coffee without sugar, please.A. anyB. someC. anythingD. something17. It’s half past nine now, I think we had better home.A. goB. goesC. to goD. going18. Do you know her well?Sure. We friends since ten years ago.A. areB. wereC. have beenD. will be19. Tim me if he my message.A. will call, getsB. will call, will getC. calls, will getD. calls, gets20. Is your sister now?Yes, she is. And my family members are preparing a party for her birthday next month.A. nineteenth; twentiethB. nineteenth; twentyC. nineteen; twentithD. nineteen; twentieth21. The expert will give us suggestions how to improve our memory.A. onB. withC. inD. to22. My father usually gets up than my mother.A. much earlyB. much earlierC. many earlyD. more earlier23. After doing some exercise, our bodies became .A. relaxing; relaxingB. relaxed; relaxedC. relaxing; relaxedD. relaxed; relaxing24. I won’t feel happy I may go shopping every Sunday, because I love shopping very much.A. whenB. ifC. sinceD. unless25. We had trouble our way out of the place.A. findingB. findC. to findD. for finding第二节语法选择(共10小题,每小题0.5分,满分5分)Saving electricity and water is important in our life. There are 26 little things for us to do at home to help save the Earth. They’re small, but27 people do the same thing and make a great 28 . By making some small changes to the way you do things at home, you are 29 our planet day by day.You can spend 30 and improve your health better at the same time, so helping to save the environment 31 a good exercise!You can use windows to make the house good to live in. You can keep windows and doors32 to keep the house warm in winter and open in summer. The wind will often keep you as cool as33 the open air.And you must do something 34 water. The water that you use in the kitchen can also be used to wash the rice or water the flowers, and it’s very good for 35 . Please always remember to turn off the lights when you leave.26. A. much B. many C. few D. little27. A. thousand B. thousands C. thousand of D. thousands of28. A. different B. differently C. difference D. differences29. A. help B. helps C. helped D. helping30. A. less B. more C. a lot D. a little31. A. was B. is C. were D. are32. A. close B. to close C. closed D. be closed33. A. at B. in C. by D. on34. A. save B. saved C. saving D. to save35. A. it B. you C. them D. us三、完形填空(共10小题,每小题1分,满分10分)How to get well fast when you are ill36. A. advice B. thoughts C. feelings D. medicine37. A. keep B. work C. stay D. eat38. A. better B. slower C. sooner D. faster39. A. doctor B. market C. shop D. teacher40. A. look B. taste C. seem D. get41. A. food B. bread C. fruit D. rice42. A. sunny B. cloudy C. cool D. fine43. A. develop B. control C. smell D. feel44. A. dry B. clean C. wet D. healthy45. A. before B. after C. when D. while四、阅读理解(共15题,每小题2分,满分30分)ATaylor Burghard is a young businesswoman. She grew up around technology in her parents' computer shop. She even helped her dad make a sale when she was just 2 years old: she showed a customer how easy it was to use a computer. Now, she has her own business. “We recycle old computer pieces and turn the m into jewelry," she said.Taylor Burghard sells her jewelry, which is made of keyboard keys, memory hardware and other computer parts.Taylor sells her jewelry online, in her parents' store and in a California toy store where her aunt worksas a buyer. Taylor’s friends buy her jewelry for gifts. She said it made her feel so happy when people bought the jewelry.Taylor said she was also happy to find a way to help recycle old computers and reduce electronic waste. Her dad even asked other businessmen to send their old keyboards and computer parts to the store for Taylor to use.She has three goals. "I want to help pay for college, learn about business and have fun," she said.( ) 46. How did Taylor help her dad make a sale when she was 2 years old?A. She shouted aloud.B. She introduced a computer.C. She showed it was easy to use a computer.D. She showed it was interesting to use a computer.( )47. Taylor sells her jewelry _______.①in her classroom ②in her parents' store③in a California toy store ④on the InternetA. ①②③B. ①②④C. ①③④D. ②③④( ) 48. What does the underlined word "buyer" mean?A. Someone who buys something.B. Someone who owns something.C. Someone whose job is to buy things for a shop.D. Someone whose job is to sell things for a shop.( ) 49. How many goals does Taylor have?A. Two.B. Three.C. Four.D. Five.( ) 50. Which of the following can be used to describe Taylor?A. Clever.B. Stupid.C. Funny.D. Friendly.BBefore the midnight on November10, 2014, Shi Hailin and his wife sat waiting in front of their computer, ready to buy something online for their new house. When the shopping was over,they spent more than 20,000 yuan and bought two air conditioners,a television,a fridge and a washing machine. “We saved 3,000 yuan at least that day, buying online that day is much cheaper than in shops as usual,”said Shi,a30-year-old manager in Beijing.On November11, a shopping day, is named singles day in China. Taobao made in a total of 60 billion yuan purchase(销售) of goods. Over the past five years, besides Taobao, other websites like 360 , , have joined in Singles Day online sales.Li shengkai, a 30-year-old office lady in Guangdong, who earns 8000 yuan a month, spent about 50% of her salary(薪水) buying clothes on Singles Day.”I like watching on the Internet all the day with my mobile phone, before buying, I went to the shop to try on the clothes I ’d like to buy, then bought them online at half price,” She said. “but I usually buy some more things I don’t need online too”Experts said, E-shopping is a new way for people to buy things, it’s convenient and cheap, more and more people like shopping in this way. But for the same reasons, people spend more money than they need, so we should think more carefully before we buy.51. How much money did the Shi Hailin save?A. 20000B. 6000C. 4000D. 300052. What’s the problem of Li Shengkai?A. She bought some useless things online too.B. She didn’t spend all her money to buy clothes.C. She tried on the clothes before buying online.D. She earns too little money a month.53. How many shopping websites does the passage talk about?A. 2B. 3C. 4D. 554. Which following statement is NOT true according to the passage?A. Taobao sold 60 billion yuan of goods on the Singles Day in 2014.B. It’s more convenient and cheaper to buy in shop than online.C. People can do online shopping on the computers and mobile phones.D. E-shopping is a popular way now.55. What’s the best title of this passage?A. E-shopping is bad for usB. We should buy onlineC. A new way of shoppingD. Save money on the internet.CDo you need useful and interesting books? Here we’ve got plenty for you.Successful FishermenFishing is a healthy hobby. You can enjoy fresh air when you go fishing in the countryside. This bookwill teach you how to choose fishing places and how to make good fishing rods (竿) easily. Many kindsof fishing skills are shown in the book. Read it and you will become a more successful fisherman.Best LearnersThis book can give you the answers to the questions most often asked by parents, teachers and students themselves. Read this book and learn:●What the three difficulties in study are and what to do with them.●What to do if you are not interested in a subject you are studying.●Twenty-six simple exercises to help you study easily and fast.You will get more from this book. For younger students, you can buy Learn in Study for Beginners.It is easier to understand.How to Keep PetsA pet can be our best friend. Do you have pets in your house? Are they in good shape? This booknot only offers you many colorful pictures of lovely pets, but also provides you with the knowledge about:●How to choose right pets for yourself.●How to build houses or nests (窝) for your pets.●How to feed the pets and how to keep them clean.Buy this book and you will learn more.We have many other books on sale. For more information enter . If you buy twoor more books at a time, you’ll get 10% off.56. If you buy and read Successful Fishermen, you will ______.A. go to the countrysideB. know where to buy fishing rodsC. know how to cook fishD. learn how to choose fishing places57. There are many pictures in _____ according to the passage.A. Best LearnersB. Successful FishermenC. How to Keep PetsD. Learn to Study for Beginners58 You can _____ for more information about other books according to the passage.A. call the writerB. go to the shopC. search the InternetD. ask the clerk59. The writer wrote this passage in order to _____ .A. increase sales of the booksB. buy useful and interesting booksC. tell people how to keep petsD. teach students to study easily and fast60. You can most probably (可能) find this passage in a ______.A. storyB. reportC. dictionaryD. newspaper五、写作(共三节,满分25分)第一节单词拼写(共5题,每小题1分,满分5分)根据下列句子以及所给单词的首字母写出所缺单词。
2015年广州荔湾区八年级上期末考试英语试题
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广州荔湾区八年级上期末考试二.语言知识运用(共两节,满分 15 分)第一节单项选择(共 10 小题每题 1 分共 10 分)16.--There is ________ outside. Please go and open the door. --Yes, mum.It may be dad.A. somebodyB. somethingC. anythingD. anybody17. T he blue whale is one of _________ animals on Earth.A. largeB. the largestC. the largerD. largest18. -- _________ you ever ________ to Buckingham Palace?--Yes. I _________ there last year.A. Did…go; have beenB. Did…go; have goneC. Have…gone; wentD. Have…been; went19. Y ou had better ________ the light. I want to have a rest now.A. not to switch offB. not switch offC. switch offD. to switch off20. W e didn’t have the sports meeting yesterday ________ it rained heavily.A. because ofB. becauseC. soD. but21. T om has just had his __________ birthday.A. fourB. fourteenC. then fourteenthD. fourteenth22. Y ou will not get good marks in the oral exam _____you’ve improved your spoken English.A. unlessB. ifC. whenD. where23. I have been a member of the Singing Group __________ last month.A. forB. 不填C. inD. since24.--I don’t have enough money for the Apple laptop. --How aboutthis one? It’s much __________.A. cheapB. cheaperC. cheapestD. the cheapest25. Our class will _________an English play in the School Talent Show.A. put downB. put upC. put onD. put away第二节语法选择(共 10 小题每题 1 分共 10 分)This is a story about two wise men-Zhuge Liang and Zhou Yu. The Chinese people 26 it for many, many years.One day, Zhou Yu gave Zhuge Liang 27 impossible task. He asked him to make 100000 arrows within ten days “No problem,” Zhuge Liang said; “I 28 you 100000 arrows in three days.”Zhuge Liang asked his soldiers to fill 20 large boats 29 many straw men. In the early morning of the third da y, Zhuge Liang’s soldiers sailed the boats towards the camps of Cao Cao’s1 / 7army on30side of the river, The soldiers shouted and beat their drums31When Cao Cao’s soldiers heard the sounds, they thought they were under attack.32 , they could not see through the thick fog on the river. Cao cao ordered his soldiers 33 arrows towards the sounds of the drums and the shouting. Zhuge liang’s boats were soon full of arrows.Zhuge Liang’s soldiers then turned the boats around and shouted, “Thank you for34arrows, Cao Cao.” Zhuge Liang took all these arrows to Zhou Yu.35were morethan100000 of them.26. A. told B. tell C. have told D. are telling27. A. a B. an C. the D. 不填28. A. bring B. brought C. have brought D. will bring29. A. of B. in C. with D. at30. A. the other B. the others C. another D. other31. A. loud B. loudly C. louder D. loudest32. A. Or B. So C. And D. However33. A. to shoot B. shoot C. shooting D. shoot34. A. his B. your C. their D. our35. A. They B. Their C. There D. Theirs三完型填空(共 10 小题每小题 1 分共 10 分)Thousands of years ago, human didn't live in towns. Sometimes they would live in caves or build camps in the forest.Only about thirty people 36 in each camp. The men would go hunting while the women and children 37 food from the trees around the camp. All the food was 38 betweeneveryone in the group. Every few weeks they moved to another place to find more food. It was a simple life, but people had to be 39 They had to make everything that they needed, and theyhad to know a lot about plants and animals.Nowadays most people live in towns and cities, and they work in offices and factories. Life is 40 than in the old days. There are fewer 41 , but there is less excitement. Some people go 42 excitement—sailing round the world, climbing mountains, or exploring caves. Most people look forward to the 43 , a time when they can enjoy a change from their normal life. For some this means going camping. But camping today is 44 from camping in the past. Gas cookers, ready-made food and air-beds mean people can camp much more 45 than they did in the old times.36. A. lived B. talked C. came D. danced37. A. planted B. collected C. watched D. bought38. A. found B. used C. shared D. sold39. A. polite B. kind C. careful D. clever40. A. worse B. faster C. easier D. harder41. A. dangers B. stories C. people D. animals2 / 742. A. waiting for B. looking for C. turning on D. putting on43. A. dreams B. gifts C. meals D. holidays44. A. away B. different C. free D. far45. A. slowly B. terribly C. comfortably D. hopefully四、阅读理解(共 10 小题每小题 1 分共 10 分)(A)I was an exchange student in America for a year. I want to tell you about a year in America. I stayed in with a host family in a small town in Indiana. I experienced a big culture shock there. So many things were similar: the language, the food, the land, and even the school.I soon discovered that the English spoken by Americans is a bit different from British English. For example, they use “vacation” instead of “holiday”. But my main problem is the accent. I could hardly understand anything for the first few weeks. But after a while, I got used to it.The second difference was the food. After fourteen years of eating Chinese food, it was a big shock to eat Western food all the time. The food eaten in Indiana was quite different to the kind of American food I eat in Guangzhou. I had to learn some new table manners, too. For example, how to use knives and forks properly.\The third difference was the land itself. The countryside, compared to Guangzhou, is completely flat. People lived in large houses, not tiny apartments. I could not see the sea or mountains, or any skyscrapers(摩天大楼).I went to a local high school, and that was a big shock, too. The students there don’t wear uniforms. They wear casual clothes. I felt uneasy when I went to school wearing a T-shirt and blue jeans! I liked the school because the classes were small—around fifteen to twenty students, and I could select my own subjects. During the year, there were many moments: playing in the snow in the winter, and going on visits to Niagara Falls and Florida.It was an exciting year, and now I understand a little more about American culture. My American friends asked me a lot of questions about life in China, and this made me think a lot about my culture, too.46. Where did the writer stay as an exchange student?A. In IndianB. In GuangzhouC. In the UKD. In a town in America3 / 747. How many culture shocks are mentioned in this passage?A. TwoB. ThreeC. FourD. Five48.Which of the following is True according to the passage?A.The writer’s host family was in India.B.The writer lived in a big house with mountains around.C.The writer could eat the same American food as in Guangzhou.D.The writer was fourteen years old when he took part in the exchange program.49.What made the author feel uneasy in the local high school?A.He wore casual clothes instead of school uniforms.B.He couldn’t see the mountains or any skyscrapers.C.The classrooms are smaller than the ones in Guangzhou.D.He didn’t know how to choose his subjects because they were very diff icult.50.What’s the best title for this passage?A. A nice tripB. Big culture shocksC. School life in AmericaD. An exciting moment(B)Stonehenge is an ancient monument(遗址)in England.At around the same time as the ancient Egyptians were building the pyramids, the first stones arrived here at Stonehenge. The secret of this stone is that they are only found in the Brescelly Mountains in South Wales, nearly 150 miles away. Now it takes you about five hours to drive all the way.It was a hard job to move these stones from Wales, because there were about 80 of them here at Stonehenge weighing up to four tons each. The stones were brought by boat from the mountains and pulled from the coast by sledge(雪橇) to the place.After nearly 5,000 years, Stonehenge is still standing. We now know how it was built. The question "why" is still a big problem.Now, although many of the original stones were removed, this place still attracts nearly five thousand tourists every day.(See Britain history)51. Where is Stonehenge?A. In the USAB. In IndiaC. In EgyptD. In the UK52. Where did the stones of Stonehenge come from?A. EgyptB. EnglandC. South WalesD. Huang Mountains4 / 753. How long does it take to drive all the way from Wales to Stonehenge?A. 5 hoursB. 50 hoursC. 80 hoursD. 150 hours54. W hat’s the meaning of underlined word “attracts”?A. 存在B. 吸引C. 组建D. 参观55. W here can you probably read this passage?A. In a dictionaryB. In a novelC. In anadvertisementD. In an encyclopedia(C )“No man is an island” is a well -known line from John Donne’s Devotion (约翰多恩的奉献-诗集). It was written more than three hundred years ago. Even now people still agree with him. No one can live a completely isolated life. Without other people, life will become empty and sad. We all need to have friends.For some of us, although making friends is not difficult, feeling shy, we may not want tomake the first move. It is also difficult at times to keep the friends we already have.There are many books about friendship, but Dale Carnegie’s How to Win Friends andInfluence People , written in 1936, is the most famous. It has been sold millions of copies and put into 28 languages.Dale’s advice seems to be simple, but it c an help you. Do you need to change the way you act?Here is the list of advice from his book:1. Be friendly and polite.Always greet with a smile. Remember to say “Thank you” and try to be as helpful as you can.2. Go out of your way to be nice.Find some time to do special things for other people. Making some soup for a sick neighbour may seem like a little thing to you, but it will make your neighbor feel a lot better.3. Remember names.They say that the sweetest music to a person’s ears is the s ound of his or her own name.4. Be open-minded.Try to understand other people’s ways and ideas and learn something from them.5. Listen patiently.When someone is talking to you, look at him or her, listen carefully and say something when necessary.56.The underlined sentence “No one can live a completely isolated life.” means “___________”.A.No one can live a hard life.B. No one can live alone.C. No one can live without difficulty.D. No one can live on an island.57.What is the passage mainly about?A.Suggestions about making friendsB. A show about friendshipC. Getting to know othersD. Advice on how to become smarter58.How can people show that they are friendly and polite?A.By r emembering others’ names.B. By understanding other people’s ideas.C. By always smiling at others.D. By looking at others when they are talking.59.Why is it difficult for some people to make friends?A.Because their lives are empty and sad.B. Because they are too old to make friends.C. Because they don’t want to make the first step.D. Because they don’t want to move out of the island.60.Which of the following is true about Dale Carnegie’s book?A.It has five chapters.B. It was written in 1963.C. It can only be read in English.D. It has been bought by millions of people.五、写作(共两节,满分25分)第一节单词拼写(共5小题,每小题1分,共5分)61. English can give the students a c_______________ to speak English in public.1.Mr. Bean seems to be a little s______________, but quite lovely.2.Jane, I’ll come to your birthday party tomorrow night, Ip_______________.3.She is out of work at the moment so she has to d_______________ on herparents.4.The s_______________ of the word “brian” is wrong. It should be“brain”.第二节完成句子(共5小题,每小题2分,共10分)66.我计划通过电子邮件与老同学保持联系。
2014-2015学年荔湾区八年级数学第一学期期末教学质量检测试卷+答案.
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2014-2015学年第一学期期末教学质量检测八年级数学本试卷分选择题和非选择题两部分,共三大题23小题,共4页,满分100分.考试时间90分钟,可以使用计算器.注意事项:1. 答卷前,考生务必用黑色字迹钢笔或签字笔将自己的姓名和考生号填写在答题卡指定的位置上.2. 选择题每小题选出答案后,用2B 铅笔把答题卡上对应题目的答案标号涂黑;如需改动,用墙皮擦干净后,再选涂其它答案,答案不能答在问卷上.3. 非选择题必须用黑色字迹的钢笔或签字笔作答,涉及作图的题目,用2B 铅笔画图.答案必须卸写在答卷各题目指定区域内的相应位置上;如需改动,先划掉原来的答案,然后再写上新的答案;改动的答案也不能超出指定的区域.不准使用铅笔(除作图外)、圆珠笔和涂改液.不按以上要求作答的答案无效.一、选择题(本大题共10小题,每小题2分,共20分.在每小题给出的四个选项中,只有一项是符合题目要求的.)1.用科学记数法表示0.00000506 =( )A .5.06×106B .5.06×10-6C .50.6×10-7D .506×10-8 2.如果把分式xx y+的x 和y 都扩大3倍,那么分式的值( ). A .扩大3倍 B .缩小为原来的13C .不变D . 扩大6 倍 3.要使x 2+4x +m 是完全平方式,那么m 的值是( ).A .4B .8C .±4D . 164.计算223(-)(3)4x y z xy ÷-正确的是( ). A . 14xyz B . 94xyzC .294x zD . 214x z5.下面是一些著名汽车品牌的标志,其中不是轴对称的图形是().A.B. C. D.6.三角形的一个外角是锐角,则这个三角形的是().A.锐角三角形B.直角三角形C.钝角三角形D.不能确定7.以下长度的线段为边,可以作为一个三角形的是().A.10cm,20cm,30cm B.10cm,20cm,40cmC.10cm,40cm,50cmD.20cm,30cm,40cm∆≅∆,则需添加的条件是().8.如图,AB=DB,BC=BE,要使AEB DCBA.AB=BC B.AE=CD C.AC=CD D.AE=AC第8题第9题第10题∆≅∆,且∠O=65°,∠C=20°,则∠OAD=().9.如图,若OAD OBCA.20°B.65°C.86°D.95°∆是等边三角形,AB=6,BD是∠ABC的平分线,延长BC到E,使CE=CD,10.如图,若ABC则BE=().A.7B.8 C.9 D.10二、填空题(本大题共6小题,每小题3分,共18分.)11.计算:3-3=_______.12.如图,垂直平分线段AB,且垂足为M,则图中一定相等的线段有_______对.13.如果点A的坐标是(3,-2),点B的坐标是(3,2),那么点A和点B关于________轴对称.14.一个多边形的每一个外角为30°,那么这个多变形的边数是__________.15.如果10m =4,10n =12,那么10m+n =__________. 16.如图,在Rt ABC ∆中,∠C =90°,AC =3, BC =4,AD 平分∠CAB 交BC 于D ,DE ⊥AB 于E , 则BDE ∆的周长等于__________.一、解答题(本大题共7小题,共62分.解答应写出文字说明、证明过程或演算步骤.) 17.(每小题4分,本题满分8分)计算: (1) (2x -3)(x -5)(2) (3a 2)2-5a 2(2a 2+3a 2b 4)18.(每小题5分,本题满分10分)分解因式: (1) 4ma 2-4mb 2(2) 7(x 2-y 2)-6x (x -y )+16y 219.(每小题5分,本题满分10分)计算: (1)2212--yx y x y- (2) 22269--34a a a a a +-+-20.(本题满分8分)如图,已知∠A =∠D ,∠ABC =∠DCB ,求证:AC =DB .第12题第16题 第20题21.(本题满分8分)如图,在ABC ∆中,点D 在BC 上,A C=CD ,∠B=30°,∠ADB=100°.(1) 作AB 的垂直平分线EF ,分别交BC 、AB 于E 、F (不写作法,保留作图痕迹); (2) 连结AE ,求∠C 与∠AED 的大小.22.(本题满分8分)列方程解应用题:汛期将至,解放军某连兵官为驻地民众着想,计划加固驻地附近18千米的河堤.根据气象部门预测,今年的汛期有可能提前,因此,官兵们发扬我军不怕苦、不怕累的优良传统,早出晚归,使实际施工速度提高到原计划的1.5倍,结果比计划提前6天完成.求该连队实际每天加固河堤多少千米?23.(本题满分10分)如图,已知ABC ∆为等边三角形,点D 由点C 出发,在BC 的延长线上运动,连结AD ,以AD 为边作等边三角形ADE ,连结CE .(1) 请写出AC 、CD 、CE 之间的数量关系,并证明;(2) 若AB =6cm ,点D 的运动速度为每秒2cm ,运动时间为t 秒,则t 为何值时,CE ⊥AD ?第21题第23题第23题备用图2014~2015学年第一学期期末考试八年级数学参考答案一、选择题(每小题2分,共20分)二、填空题(每小题3分,共18分)三、解答题(共62分)注:下面只是给出各题的一般解法,其余解法对应给相应的分数17. (每小题4分,本题满分8分)计算:(1)原式=2210315x x x --+ ………………………………3分=221315x x -+ ………………………………4分(2)原式=444491015a a a b -- ………………………………3分=44415b a a -- ………………………………4分18. (每小题5分,本题满分10分)分解因式:(1)原式=224()m a b - ………………………………2分=4()()m a b a b +- ………………………………5分(2)原式=2222776616x y x xy y --++ ………………………………2分 =2269x xy y ++ ………………………………3分=2(3)x y + ………………………………5分19. (每小题5分,本题满分10分)计算: (1)原式=2()()()()x y yx y x y x y x y +--+-+ ………………………………2分=2()()x y yx y x y +--+ ………………………………3分=()()x yx y x y --+ ………………………………4分=1x y+ ………………………………5分 (2)原式=22(3)3(2)(2)a a a a a +-⋅-+- ………………………………3分 =32a a -- ………………………………5分20. (本题满分8分)证明:∵∠A=∠D ,∠ABC =∠DCB ,BC =CB ,……………………………4分∴△ABC ≌△DCB , ………………………………6分 ∴AC=DB . ………………………………8分21. (本题满分8分)(1)如图; ………………………………2分(2)∵∠ADB =100°,∴∠ADC =80°, …………………3分FEABCD∵AC=CD,∴∠DAC=∠ADC=80°,…………………4分∴∠C=20°,…………………5分由(1)知,EF垂直平分AB,∴AE=BE,…………………6分∴∠BAE=∠B=30°,…………………7分∴∠AED=60°…………………8分22.(本题满分8分)解:设原计划每天加固河堤x千米,……………………………1分根据题意,得:181861.5x x-=……………………………5分解得x=1.………………………………6分经检验,x=1是原分式方程的根.………………………………7分1.5x=1.5,答:该连队实际每天加固河堤1.5千米.………………………………8分23.(本题满分10分)(1)AC+CD=CE ……………………………1分证明:∵△ABC和△ADE为等边三角形,∴AC=AB,AE=AD,∠BAC=∠DAE=60°,…………………………2分∴∠BAD=∠CAE,…………………………3分∴△ACE≌△ABD …………………………4分∴BD=CE,…………………………5分∴AC+CD=BC+CD=BD. …………………………6分(2)∵△ADE为等边三角形,CE AD⊥,∴CE是△ADE的边AD的垂直平分线,…………………………8分∴CD= CA= AB=6,…………………………9分∴3t . …………………………10分第23题E。
广东省广州市荔湾区2016-2017学年八年级第一学期期末教学质量检测物理答案(word版)
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2016 学年度第一学期期末教学质量检测 八年级物理 参考答案及评分标准一、选择题 (说明:各小题评分细则由组内统一制定)二、填空作图题(每空 1 分,每图 3 分,共 30 分) 13.凝华 熔化 较高 (每空 1 分) 14.甲 乙 乙 (每空 1 分) 15.(1)15 静止 (2)5 大于 (3)2.5 9 (每空 1 分)16.(作图 3 分)A17.(1)(如右图,1 分) (2)(如右图,2 分)(3)实像 倒立 (每空 1 分) 18.液化 放热 汽化 吸热(每空 1 分) 19.变小 放大镜 变大非晶体 凝固 1.00 (每空 1 分)三、解析题(20 题 9 分,21 题 7 分,共 16 分)20.(1)该路段限速 100km/h 90km/h 不会(每空 1 分,共 3 分)1 (2)解t = 10min = h (1 分)6v = S = 15km = 90km/h (3 分)t1 h6 因为 90km/h<100km/h ,所以采用“区间测速)这辆轿车在该路段不会被判超速(2 分)21.(1)解: S = v t = 3.0⨯108 m/s ⨯1.6⨯10-6s = 480m (3 分)S 480m冰孔深度(2)10000(2 分)h = == 240m (2 分) 2 2四、实验探究题(第 22 题 8 分,第 23 题 6 分,第 24 题 4 分,共 18 分) 22.(1)B 39晶体 (2)吸收 (3)液 603(4)快 (每空 1 分)23.(1)v =s /t(2)5680.07快(3)小(每空 1 分) 24.b .蜡烛 B 的像与蜡烛 A 完全重合c .蜡烛 B 到玻璃 MN 的(每空 2 分)题号 答案1 D2 B3 D4 C5 B6 B7 C8 D9 A10 C11 A12 A。
2015.1荔湾区八上数学期末考
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广东省广州市荔湾区八年级(上)期末数学试卷一、选择题(本大题共10小题,每小题2分,共20分.在每小题给出的四个选项中,只有一项是符合题目要求的.)1.(2分)(2014秋•荔湾区期末)用科学记数法表示0.00000506()A.5.06×106B.5.06×10﹣6C.50.6×10﹣7D.506×10﹣82.(2分)(2014秋•荔湾区期末)如果把分式的x和y都扩大3倍,那么分式的值()A.扩大3倍 B.缩小为原来的C.不变 D.扩大6 倍3.(2分)(2014秋•荔湾区期末)要使x2+4x+m是完全平方式,那么m的值是()A.4 B.8 C.±4 D.164.(2分)(2014秋•荔湾区期末)计算正确的是()A.B.C.D.5.(2分)(2014秋•荔湾区期末)下面是一些著名汽车品牌的标志,其中不是轴对称的图形是()A.B.C.D.6.(2分)(2014秋•荔湾区期末)三角形的一个外角是锐角,则此三角形的形状是()A.锐角三角形B.钝角三角形C.直角三角形D.无法确定7.(2分)(2014秋•荔湾区期末)以下长度的线段为边,可以作为一个三角形的是()A.10cm,20cm,30cm B.10cm,20cm,40cmC.10cm,40cm,50cm D.20cm,30cm,40cm8.(2分)(2014秋•荔湾区期末)如图,AB=DB,BC=BE,要使△AEB≌△DCB,则需添加的条件是()A.AB=BC B.AE=CD C.AC=CD D.AE=AC9.(2分)(2014秋•荔湾区期末)如图,若△OAD≌△OBC,且∠O=65°,∠C=20°,则∠OAD=()A.20°B.65°C.86°D.95°10.(2分)(2014秋•荔湾区期末)如图,若△ABC是等边三角形,AB=6,BD是∠ABC 的平分线,延长BC到E,使CE=CD,则BE=()A.7 B.8 C.9 D.10二、填空题(本大题共6小题,每小题3分,共18分.)11.(3分)(2014秋•荔湾区期末)计算:3﹣3=.12.(3分)(2014秋•荔湾区期末)如图,CD垂直平分线段AB,且垂足为M,则图中一定相等的线段有对.13.(3分)(2014秋•荔湾区期末)如果点A的坐标是(3,﹣2),点B的坐标是(3,2),那么点A和点B关于轴对称.14.(3分)(2014秋•荔湾区期末)一个多边形的每一个外角为30°,那么这个多边形的边数为.15.(3分)(2014秋•荔湾区期末)如果10m=4,10n=12,那么10m+n=.16.(3分)(2014秋•荔湾区期末)如图,在Rt△ABC中,∠C=90°,AC=3,BC=4,AD平分∠CAB交BC于D,DE⊥AB于E,则△BDE的周长等于.三、解答题(本大题共7小题,共62分.解答应写出文字说明、证明过程或演算步骤.)17.(8分)(2014秋•荔湾区期末)计算:(1)(2x﹣3)(x﹣5)(2)(3a2)2﹣5a2(2a2+3a2b4)18.(10分)(2014秋•荔湾区期末)分解因式:(1)4ma2﹣4mb2(2)7(x2﹣y2)﹣6x(x﹣y)+16y2.19.(10分)(2014秋•荔湾区期末)计算:(1)(2).20.(8分)(2014秋•荔湾区期末)如图,已知∠A=∠D,∠ABC=∠DCB,求证:AC=DB.21.(8分)(2014秋•荔湾区期末)如图,在△ABC中,点D在BC上,AC=CD,∠B=30°,∠ADB=100°.(1)作AB的垂直平分线EF,分别交BC、AB于E、F(不写作法,保留作图痕迹);(2)连结AE,求∠C与∠AED的大小.22.(8分)(2014秋•荔湾区期末)汛期将至,解放军某连官兵为驻地民众着想,计划加固驻地附近18千米的河堤.根据气象部门预测,今年的汛期有可能提前,因此官兵们发扬我军不怕苦,不怕累的优良传统,早出晚归,使实际施工速度提高到原计划的1.5倍,结果比计划提前6天完成.求该连队实际每天加固河堤多少千米?23.(10分)(2014秋•荔湾区期末)如图,已知△ABC为等边三角形,点D由点C出发,在BC的延长线上运动,连结AD,以AD为边作等边三角形ADE,连结CE.(1)请写出AC、CD、CE之间的数量关系,并证明;(2)若AB=6cm,点D的运动速度为每秒2cm,运动时间为t秒,则t为何值时,CE⊥AD?2014-2015学年广东省广州市荔湾区八年级(上)期末数学试卷参考答案一、选择题(本大题共10小题,每小题2分,共20分.在每小题给出的四个选项中,只有一项是符合题目要求的.)1.B 2.C 3.A 4.A 5.D 6.B 7.D 8.B 9.D 10.C二、填空题(本大题共6小题,每小题3分,共18分.)11.12.3 13.x 14.12 15.48 16.6三、解答题(本大题共7小题,共62分.解答应写出文字说明、证明过程或演算步骤.)17.18.19.20.21.22.23.。
广东省广州市荔湾区2015-2016学年八年级上学期期末考试语文试题(word版附答案)
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2015-2016 学年第一学期荔湾区期末初二统考试卷和答案(语文科)本试卷共6 页,分三部分,共19 题。
全卷100 分,考试用时120 分钟。
注意事项:1. 答卷前,考生务必在答题卡上用黑色字迹的钢笔或签字笔填写自己的考生号、姓名;同时填写考场试室号、座位号,在用2B 铅笔把对应的号码的标号涂黑。
2. 选择题每小题选出答案后,用2B 铅笔把答题卡上对应的题目选项的答案信息点涂黑;如需改动,用橡皮擦掉原来的答案后,在填涂其他答案。
答案不能答在试卷上。
3. 所有非选择题的答案必须用黑色字迹的钢笔或签字笔写在答题卡各题目指定区域内的相应位置上;如需改动,先花掉原来的答案,然后再写上新的答案,改动后的答案也不能超出指定的区域;不准使用铅笔、圆珠笔和涂改液。
不按以上要求作答的答案无效。
4. 考生必须保持答题卡的整洁,考试结束后,将本试卷和答题卡一并交回。
第一部分积累与运用(共25 分)一、(6 题,15 分)1、下题词语中,加点字读音全部正确的一组是()(2 分)A.绥.靖(tuǒ) 嫣.红(yān)淤.泥(yū)B.仄.歪(zâ)匀称.(chēng)夜阑.(lán)C.尴.尬(gān)劫难.(nàn)幽咽.(yâ)D.愧怍.(zuò)差.使(chāi)篆.章(suàn)2、下列词语中,没.有.错别字的一项是()(2 分)A.技俩缓冲巧妙绝伦B.嶙峋繁衍五彩斑斓C.诘问绮丽长途拔涉D.取缔颓搪因地制宜3、下列句子中,加点词语使用不.正.确.的一项是()(2 分)A.那天我经过母校,发现原来的平房已经销.声.匿.迹.,新的校舍拔地而起。
B.如此机密的事情,他怎么能在大.庭.广.众.之下如此肆无忌惮的大声讨论呢?C.正在他束.手.无.策.之际,老师的一席话让他茅塞顿开,他决定立刻照办。
D.陈重素来是个说话直爽的人,但今天却转.弯.抹.角.的,究竟是怎么了?4、下列句子中,没.有.语病的一项是()(2 分)A.张灵和肖颖一起做作业,他向他请教了两道物理难题,他都一一解答。
2016-2017广州市荔湾区八年级上数学期末试卷
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2016学年第一学期数学科八年级教学质量检测试卷本试卷共三大题23小题,共4页,满分100分.考试时间90分钟,可以使用计算器.注意事项:1.答卷前,考生务必用黑色字迹钢笔或签字笔将自己的姓名和考生号填写在答题卡指定的位置上.2.选择题每小题选出答案后,用2B 铅笔把答题卡上对应题目的答案标号涂黑;如需改动,用橡皮擦干净后,再选涂其它答案,答案不能答在问卷上. 3.非选择题必须用黑色字迹的钢笔或签字笔作答,涉及作图的题目,用2B 铅笔画图.答案必须写在答卷各题目指定区域内的相应位置上;如需改动,先划掉原来的答案,然后再写上新的答案;改动的答案也不能超出指定的区域.不准使用铅笔(除作图外)、圆珠笔和涂改液.不按以上要求作答的答案无效.一、选择题(本大题共10小题,每小题2分,共20分.在每小题给出的四个选项中,只有一项是符合题目要求的.)1. 下列运算正确的是( * ).(A )2-1=-2(B )(-1)0=1(C )(-2)2=-4(D )(-2)3=-62. 下列分式中是最简分式的是( * ).(A )11xx (B )211x x(C )42x(D )21x 3. 下列等式成立的是( * ).(A )123aba b (B )212a b a b (C )2ab a abba b(D )a a abab4. 如图所示,一扇窗户打开后,用窗钩????可将其固定,这里所运用的几何原理是( * ).(A )三角形的稳定性(B )两点之间,线段最短(C )两点确定一条直线(D )垂线段最短5. 下列各图中,正确画出????边上的高的是( * ).(A )(B )(C )(D )6. 如图,一个等边三角形纸片,剪去一个角后得到一个四边形,则图中∠??+∠??的度数是( * ).(A )180°(B )220°(C )240°(D )300°第4题第6题7. 在△ABC和△A′B′C′中,????=??′??′,∠??=∠??′,补充条件后仍不一定能....保证△ABC ≌△A'B'C',则补充的这个条件是( * ).(A)????=??′??′(B)????=??'??'(C)∠??=∠??′(D)∠??=∠??′8. 若??2-??2=3,则(??+??)2?(??-??)2的值是( * ).(A)3(B)6(C)9(D)189. 如图,????是Rt△??????斜边????上的高,将△??????沿????折叠,??点落在线段????上的??点处,若∠??=30°,则∠??????等于( * ).(A)60°(B)30°(C)45°(D)25°10. 如图,直线??是一条河,??,??是两个村庄.欲在??上的某处修建一个水泵站,向??,??两地供水,现有如下四种铺设方案,图中实线表示铺设的管道,则所需管道最短的是( * ).二、填空题(本大题共6小题,每小题3分,共18分.)11. 使分式32x有意义的x的取值范围是*.12. 如图,在△??????中,∠??=30°,∠??=50°,延长????到??,则∠??????=*°. 13. 如图所示,△??????≌△??????,∠??=70°,∠??=26°,∠??????=30°,则∠??????等于*°.14. ??是△??????三条角平分线的交点,∠??=60°,则∠??????=*°.15. 如图,在Rt△??????中,∠??=90°,∠??=30°,????-????=2,则????等于*.16. 观察下列各等式:1111212,1112323,1113434,?,根据你发现的规律计算:11111223341n n*.(??为正整数).第15题第13题第12题第9题(C)(A)(B)(D)三、解答题(本大题共7小题,共62分.解答应写出文字说明、证明过程或演算步骤.)17.(每小题4分,本题满分8分)计算:(1))3)((y xy x(2)yx y x y x 22352)24(18.(每小题4分,本题满分8分)分解因式:(1)aab42(2)2)1(9)1(124x x 19.(每小题4分,本题满分8分)计算:(1)222222510a b a bab a b(2)2222x y x xy xyxyxy20.(本题满分8分)如图,△ABC 中,点A 的坐标为(0,1),点B 的坐标为(3,1),点C 的坐标为(4,3),(1)画出△ABC 关于x 轴对称的△A ′B ′C ′;(2)如果在平面直角坐标系中存在点D ,使△ABD 与△ABC 全等(点D 与点C 不重合),直接写出所有符合要求的点D 的坐标.第20题21. (本题满分10分)如图,点D 在AB 上,点E 在AC 上,BE=CD ,∠B=∠C.求证:BD =CE .22. (本题满分10分)列方程解应用题:八年级学生在综合实践活动课进行甲、乙两种环保包装盒的手工制作.已知同样用12m 2的材料制成甲盒的个数比制成乙盒的个数少4个,且制作一个甲盒比制作一个乙盒需要多用20%的材料.求制作每个甲盒、乙盒各用多少材料?23.(本题满分10分)(1)已知:△ABC 是等腰三角形,其底边是BC ,点D 在线段AB 上,E 是直线BC 上一点,且∠DEC =∠DCE ,若∠A=60°(如图①).求证:EB=AD ;(2)若将(1)中的“点D 在线段AB 上”改为“点D 在线段AB 的延长线上”,其它条件不变(如图②),(1)的结论是否成立,并说明理由.第23题EDCBA第21题。
2016-2017广州市荔湾区八年级上数学期末试卷
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2016学年第一学期数学科八年级教学质量检测试卷本试卷共三大题23小题,共4页,满分100分.考试时间90分钟,可以使用计算器.注意事项:1.答卷前,考生务必用黑色字迹钢笔或签字笔将自己的姓名和考生号填写在答题卡指定的位置上.2.选择题每小题选出答案后,用2B铅笔把答题卡上对应题目的答案标号涂黑;如需改动,用橡皮擦干净后,再选涂其它答案,答案不能答在问卷上.3.非选择题必须用黑色字迹的钢笔或签字笔作答,涉及作图的题目,用2B铅笔画图.答案必须写在答卷各题目指定区域内的相应位置上;如需改动,先划掉原来的答案,然后再写上新的答案;改动的答案也不能超出指定的区域.不准使用铅笔(除作图外)、圆珠笔和涂改液.不按以上要求作答的答案无效.一、选择题(本大题共10小题,每小题2分,共20分.在每小题给出的四个选项中,只有一项是符合题目要求的.)1. 下列运算正确的是( * ).(A)2−1=−2(B)(−1)0=1(C)(−2)2=−4(D)(−2)3=−62. 下列分式中是最简分式的是( * ).(A)11xx--(B)211xx--(C)42x(D)21x+3. 下列等式成立的是( * ).(A)123a b a b+=+(B)212a b a b=++(C)2ab aab b a b=--(D)a aa b a b=--++4. 如图所示,一扇窗户打开后,用窗钩AB可将其固定,这里所运用的几何原理是( * ).(A)三角形的稳定性(B)两点之间,线段最短(C)两点确定一条直线(D)垂线段最短5. 下列各图中,正确画出AC边上的高的是( * ).(A)(B)(C)(D)6. 如图,一个等边三角形纸片,剪去一个角后得到一个四边形,则图中∠α+∠β的度数是( * ).(A)180∘(B)220∘(C)240∘(D)300∘第4题第6题7. 在△ABC 和△A′B′C′中,AB =A ′B ′,∠B =∠B′,补充条件后仍不一定能....保证△ABC ≌△A'B'C',则补充的这个条件是 ( * ).(A )BC =B′C′ (B ) AC =A 'C ' (C ) ∠A =∠A′ (D )∠C =∠C′8. 若 x 2−y 2=3,则 (x +y )2⋅(x −y )2 的值是( * ).(A ) 3 (B )6 (C ) 9 (D )189. 如图,CD 是 Rt △ABC 斜边AB 上的高,将 △BCD 沿 CD 折叠,B 点落在线段 AB 上的 E 点处,若∠A =30∘,则 ∠ECB 等于( * ).(A ) 60∘ (B )30∘(C ) 45∘ (D )25∘ 10. 如图,直线 l 是一条河,P ,Q 是两个村庄.欲在 l 上的某处修建一个水泵站,向 P ,Q 两地供水,现有如下四种铺设方案,图中实线表示铺设的管道,则所需管道最短的是( * ).二、填空题(本大题共6小题,每小题3分,共18分.)11. 使分式32x +有意义的x 的取值范围是 * . 12. 如图,在 △ABC 中,∠A =30∘,∠B =50∘,延长 BC 到 D ,则 ∠ACD = * °.13. 如图所示,△ABC ≌△ADE ,∠B =70∘,∠C =26∘,∠DAC =30∘,则 ∠EAC 等于 * °.14. O 是 △ABC 三条角平分线的交点,∠A =60∘,则 ∠BOC = * °.15. 如图,在 Rt △ABC 中,∠C =90∘ , ∠A =30∘ , AB −BC =2,则 AB 等于 * .16. 观察下列各等式:1111212=-⨯,1112323=-⨯,1113434=-⨯,⋯,根据你发现的规律计算:()11111223341n n ++++=⨯⨯⨯+ * .(n 为正整数). 第15题第13题 第12题 第9题(C )(A ) (B )(D )三、解答题(本大题共7小题,共62分.解答应写出文字说明、证明过程或演算步骤.)17.(每小题4分,本题满分8分)计算:(1) )3)((y x y x -+(2) y x y x y x 22352)24(÷-18.(每小题4分,本题满分8分)分解因式:(1) a ab 42-(2) 2)1(9)1(124-+--x x19.(每小题4分,本题满分8分)计算: (1) 222222510a b a b ab a b-∙- (2) 2222x y x xy x y x y x y ++-+--20.(本题满分8分)如图,△ABC 中,点A 的坐标为(0,1),点B 的坐标为(3,1),点C 的坐标为(4,3),(1)画出△ABC 关于x 轴对称的△A′B′C′;(2)如果在平面直角坐标系中存在点D ,使△ABD 与△ABC 全等(点D 与点C 不重合),直接写出所有符合要求的点D 的坐标.第20题21. (本题满分10分)如图,点D 在AB 上,点E 在AC 上,BE =CD ,∠B =∠C .求证:BD =CE .22. (本题满分10分)列方程解应用题:八年级学生在综合实践活动课进行甲、乙两种环保包装盒的手工制作.已知同样用12m 2的材料制成甲盒的个数比制成乙盒的个数少4个,且制作一个甲盒比制作一个乙盒需要多用20%的材料.求制作每个甲盒、乙盒各用多少材料?23. (本题满分10分)(1)已知:△ABC 是等腰三角形,其底边是BC ,点D 在线段AB 上,E 是直线BC 上一点,且∠DEC =∠DCE ,若∠A =60°(如图①).求证:EB =AD ;(2)若将(1)中的“点D 在线段AB 上”改为“点D 在线段AB 的延长线上”,其它条件不变(如图②),(1)的结论是否成立,并说明理由.第23题E D C B A 第21题。
广州市荔湾区2015-2016学年八年级上期末物理试题附答案
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广州市荔湾区2015-2016学年八年级上期末物理试题附答案八年级物理试题本试卷分第一部分(选择题)和第二部分(非选择题)。
第一部分1 至3 页,第二部分3 至7 页,共7 页。
总分100 分。
考试时间80 分钟。
第一部分(选择题共36 分)一、选择题(请选出一个正确或最优答案;每小题3 分,共36 分)1.在繁华的闹市设立噪声检测器,这是测定声音的()A. 音调B. 响度C. 音色D. 声速2.如图所示,A 为信号源,B 为接收器,A,B 间有一真空区域。
当信号源A 分别发射出超声波,可见光,红外线和紫外线信号时,接收器B 不能接收到的信号是()A. 紫外线B. 红外线C.可见光 D. 超声波3.加油站贴有“禁止吸烟”,“请不要使用手机”等警示语。
这是为了防止火花点燃汽油引起火灾,因为常温下汽油容易()A.液化B.气化C.凝华D.升华4.小明在一只空罐中放一枚硬币,后退到某处眼睛刚好见不到它,另一位同学慢慢让罐装水,小明在远处又看到硬币,这种现象可以用下列哪个光路图来解析()5.下列数值最接近实际情况的是() A. 一般洗澡水的温度约为60℃。
B. 42 寸液晶电视机对角线长度约42dmC. 公交车在市区的行驶速度约为60m/s D. 八年级物理课本的长度约为26cm6.如图所示的各种运动中,不属于机械运动的是()A.斗转星移 B.骏马奔腾 C.鲜花怒放 D.枯叶飘落7.如下图所示,在演示声音是由物体振动引起的试验中,将正在发声的音叉紧靠悬在旁边的轻质小球,小球被多次弹开,在此实验中小球的作用是()A. 使音叉振动的时间延长B. 使音叉振动尽快停下来C. 使声波多次反射形成回声D. 把音叉的微小振动放大,便于观察8.我国是一个缺水的国家,因而污水净化具有重要意义,下面是小明发明的太阳能净水器,该净水器在污水净化过程中发生的物态变化是()A. 先汽化,后液化B. 先熔化,后液化 C. 先升华,后凝华 D. 先汽化,后凝固9. 在探究“凸透镜的成像规律”实验中,已知凸透镜的焦距为15cm,把蜡烛放在离凸透镜10cm 处,移动光源,在光屏上将看到()A. 无像B. 正立放大的虚像C. 倒立放大的虚像D. 倒立缩小的实像10. 某同学为了探究“视力矫正”原理,利用探究凸透镜成像规律的装置做了以下实验。
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(完整word版)广东省广州市荔湾区2015-2016学年八年级上学期期末考试英语试题(word版附答案)亲爱的读者:本文内容由我和我的同事精心收集整理后编辑发布到文库,发布之前我们对文中内容进行详细的校对,但难免会有错误的地方,如果有错误的地方请您评论区留言,我们予以纠正,如果本文档对您有帮助,请您下载收藏以便随时调用。
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最后最您生活愉快 ~O(∩_∩)O ~2015-2016 学年第一学期荔湾区期末初二统考试卷和答案(英语科)二、语言知识与运用(共10 分)第一节单项填空(共10 小题,每小题0.5 分,满分5 分)从16~25 各题所给的A、B、C 和D 项中,选出可以填入空白处的最佳选项,并在答题卡上将该选项涂黑。
16.in our class playing basketball,so we are all goodat it. A .Nobody; like B Everybody; like C. Nobody; likes D. Everybody;likes17.W ith the help of miss Li,I speak English in myclass. A better B. the best C. well D. much better18.-Do you know her well?-Sure. We friends since ten yearsold. A .are B were C. have beenD .will be19.T om me for help he has becomepopular. A. will ask, if B .will ask ,then C .asks, whileD. asks ,since20.A t the start of country, cars becamepopular. A. twenty B. twenties C. twentieth D. thetwentieth21.T he expert will give us some advice how to improve ourmemory. A. on B. with C. in D .to22.W e cannot change the past. You it again.A .had not better say B. had better notsay C. had better not to say D. hadbetter say not23.A fter doing some exercise, our bodies became .A .relaxing; relaxing B. relaxed ;relaxedC. relaxing, relaxed D .relaxed, relaxing24.I nternet allows people the information they need anytime,anywhere. A .get B .got C getting D. to getit was yesterday.25.I t’s sunny today Itisn’tA.a s cold asB. as colder asC. as coldest asD. as the cold as第二节语法选择(共10 小题,每小题1 分,满分是10 分)阅读下面短文,按照句子结构的语法性和上下连贯的要求,从26~35 题各题所给的A,B,C 和D 项中选出最佳选项,并在答题卡上将该项涂黑。
Paul Lucas can often be soon walking around the city of San Francisco.26 people are surprised to see him walking 27 my shoes or socks, 28 Lucas doesn’t mind at all.He likes to walk barefoot(赤脚), and so do 640 other member of Dirty SoleSociety,the club that Lucas 29 years ago.Lucas’s idea for this is to encourage other to live 30 -free of shoes.According to Lucas,the barefoot life has many advantage, 31most important is simply that it feels good. He also says that waling barefoot allow you to experience the world directly by 32 it with your feet. In addition,the feet do not smell so much 33 they stay dry, making it hard for bacteria34 .And,of course,walking barefoot keeps your feet in good shape,so it’s actually 35 than wearing shoes.26.A.Some time B.Some times C. SometimeD.Sometimes 27.A.with B.withoutC.onD.in28.A.and B.or C.also D.but29.A.starts B.start C.started D.hasstarted 30.A.free B.freely C.freer D.lessfreely31.A.A B.An C.The D.不填32.A.touch B.touching C.touched D.to touch33.A.where B.since C.while D.become34.A.grow B.grown C.growing D.to grow35.A.health B.healthy C.healthierD.healthiest三、完型填空(共10 小题,每小题1 分,满分10 分)阅读下面短文,掌握其大意,然后从36-45 题各题所给的A,B,C 和D 项中,选出最佳选项,并在答题卡上将选项涂黑。
Do you write you own blog(博客)?Do you often36 others’ blogs on the internet? All over the world,not only famous persons but also many students use blogs as diaries and places to share the experience and 37 advice or help“I write my activities every day. 38 funny things or worries in my life.”says Lali, a 16-years-old high school student at Cambridge High school in Washington.“I like putting pictures on my blog because it can make my blog more39 and more people will like it.It’s a good way to 40 my life to the world “She has had her blog for eight months.Students like writing blogs. 41 they can write anything they want to,but don’t need to 42 any money.Once you start to write your blog,you will43 that you open up a new world.But what you write down 44 trouble you sometimes.So,use the blog carefully45 you can keep yourself away from some troubles.The blog makes everybody’s life colorful. 36.A.read B.write C.forget D.miss 37.A.learn from B.deal with C.ask for D.dependon 38.A.without B.between C.including D.besidesmon B.modern C.famousD.interesting 40.A.show B.sendC.bringD.report 41.A.Unless B.WhileC.UntilD.Because 42.A.save B.spendC.takeD.cool43.A.dream B.think C.find D.hope44.A.may B.should C.must D.can45.A.only when B.even though C.so that D.eversince四、阅读理解(共15 小题;每小题2 分,满分30 分)阅读下列三篇短文,从每题所给的A、B、C 和D 项中,并选出最佳选项,并在答题卡上将该项涂黑。
(A)For ten weeks,in a great house on the island of St. Thomas, Dr. John C Lily tried to teach a six-year-old dolphin to speak English.Margaret,an experiment(实验)helper,would likeday and night with Peter,a dolphin.And they would eat,bathe,sleep and play together from Sunday to Friday,with only Saturday off forMargaret.She lived her lifewith swimming clothes-with a coat on colder evenings,and cut her hair short so that she could get on with peter easily.After a few days,Peter was becoming more and more interested in winning her attentions.He drew a ball against her shower towel to get her to play.As a time went by,he only wanted to play ball with her and not on his own.The problem was that,just at the time peter and Margaret began to get on well just as two best friends,the experiment ended and the lab was closed.After a fewweeks,Margaret received the sad news that peter had killed himself by refusing to breathe,and sinking to the bottom of his pool. Dolphins may not speak English,but,just like humans,they know all about broken hearts.46.p eter is the name of .A.d octorB.a dolphinC.a scientistD.an experimenthelper 47.Margaret worked days a week duringthe experiment. A.four B.fiveC.sixD.seven48.T o live with the dolphin,Margaret couldn’t.A.c ut her hair shortB.have a common feel like othersC.wear swimming clothesD.eat, bathe and play together withhim 49.The ending of the story was that_ .A.Margaret didn’t leave the labB.t he dolphin could speak English atleast C.the lab was closed and thedolphin diedD.Dr. John C Lily was pleased with theexperiment. 50.From the passage,we can learnthat .A.dolphins aren’t worth studyingB.dolphins can’t be humans’ good friendsC.dolphin can’t communicate with humansD.dolphin may have feelings just likehumansChina.Have you got a story about life in China?If you do,please put your story here.Since the winter last year,the haze(雾霾)has happened a lot of times.It has done greatharm(伤害)to our daily life.More and more people have to go to see the doctor because the serious disease caused by the haze.Many traffic accidents happened and quite a lot of flights have to be put off just because of the haze weather.OnOct,30,2013, in 16-car chain collusion(连环相撞)on the highway in Tangshan,manypeople were hurt and some even died.Beijing International Airport canceled or put off nearly 76 fights on Oct,6,2013 as the result of the weather(Wu Hai, Shantou)It’s reported that 293 pedestrians(行人) die of traffic accidents every day in china.Imyself ever experienced a very terrible accident.Early last Thursday morning,I was walking on my way to school as usual.A little boy ran past me.He ran so fast when crossing the street that he didn’t notice a speeding car came round the corner.I was scared and shouted to him to shop,but it was too late.The boy was knocked down by the car.I hurried to the boy,crying for help.The boy was taken to the hospital as soon as the policemen and doctors arrived. Later,Ilearned the boy died because he lost too much blood.(Li Lan,Guangzhou)51.w hat harm does the haze cause toflights? A.Many flights have to be putoffB.Many traffic accidents happenedC.Many people were hurt in the flightsD.Many people have to go to see thedoctor52.h ow many pedestrians die of traffic accident every B.76C.293D.23953.W hy did the boy die?A.He ran too fast.B.He was hurt badly.C.Hewashitbyabus D.He lost too much blood. 54.Main idea of the second story is about.批注[lum1]: 卷子过于模糊,原文的图截下来后非常不清晰,故没有按照原文做成表格A.traffic safetyB.293 pedestriansC.the little boyD.my way toschool 55.what’s the best title for the passage?A.News on TVB.Stories onlineC.Life in the southD.Life in China(C)Children are natural scientists,very interested in the world around them.Helping them enjoy science can be easy. There’s no need for a lot of scientific terms(科学俗语)or modern labs.You only have to share your children’s interest.Firstly,listen to their questions.I once visited a classroom of seven-year-old Children to talk about science as a job.The children asked me “textbook questions”about schooling,the money I got and whether I liked my job. WhenI finished answering,we sat facing each other silently.Finally I said, “Nowthat we’ve finished with your lists,do you have questions of your own about science?”After a long walk,a boy put up his hand, “Have you ever seen a grasshopper(蚱蜢)eat?When I try eating leaves like that, I get a stomachache.Why?” Thisbegan a lot of questions that lasted nearly two hours.Secondly,give them time to think. Studies over the past 30 years have shown that, after asking a question, many teachers usually wait only one second or less for an answer, no time for a child to think. When teachers increase their “wait time”to three seconds or more, children give better answers.But in taking about science, these words make a child think that the discussion is over. Instead, keep things going by saying, “That’s interesting” or “I’ve never thought of it that way before,” or coming up with more questionsor ideas.Lastly, show; don’t tell. Let children look at their hands through a microscope(显微镜),and they’ll understand why you want to wash beforedinner. 56.How can we help children enjoy science?A.Tell them the termsB.share their interestC.Let them study in labsD.let them see the world around57.I n the second paragraph, the word “your list” mean .A.y our answer to the questionsB.your own questions aboutscience C.your question from textbookD.all the questions of yourown 58.What’s the best way for teachers to get children’s betteranswers?A.Ask them to answer quickly.B.Wait for one or twoseconds. C.Tell them to watch their language. D.Wait at leastthree seconds. 59.Which of the following ways are NOTmentioned in the passage?A.Tell children to remember facts.B.Give children time to think.C.Let children see things for themselves.D.Encourage children to ask question of theirown. 60.The writer of the passage is probably .A.a teachersB.a scientistC.a boy’s fatherD.a reporter五、写作(共三节,满分25 分)第一节单词拼写(共5 小题,每小题1 分,满分5 分)根据下列句子以及所给的单词的首字母写出所缺的单词,在填写答题卡时,要求写出完整单词。