2020人教版八年级上册期末试题(含答案)
2020年人教版八年级(上)期末数学试卷及答案

人教版八年级(上)期末数学试卷一、选择题(本大题共10小题,共40.0分)1.画△ABC一边上的高,下列画法正确的是()A. B.C. D.2.在△ABC中,∠A=∠B=∠C,则△ABC是()A. 锐角三角形B. 钝角三角形C. 直角三角形D. 无法确定3.下面四个手机应用图标中是轴对称图形的是()A. B. C. D.4.已知a+b=2,则a2-b2+4b的值是()A. 2B. 3C. 4D. 65.分式中,a,b都扩大2倍,那么分式的值()A. 不变B. 扩大为原来的2倍C. 扩大为原来的4倍D. 缩小为原来的6.方程-=0的解为()A. B. 0 C. 1 D. 无解7.将△ABC的三个顶点的横坐标不变,纵坐标均乘以-1后得到△DEF,则△DEF()A. 与关于x轴对称B. 与关于y轴对称C. 与关于原点对称D. 向x轴的负方向平移了一个单位8.把x3-2x2y+xy2分解因式,结果正确的是()A. B. C. D.9.如图,△ABC中,BC=a,AC=b,AB=c(b<c<a),BC的垂直平分线DG交∠BAC的角平分线AD于点D,DE⊥AB于E,DF⊥AC于F,则下列结论一定成立的是()A. B. C. D.10.已知x为整数,且为整数,则符合条件的x有()A. 2个B. 3个C. 4个D. 5个二、填空题(本大题共4小题,共20.0分)11.计算:(-2a2b3c)3=______.12.化简:(2a-3)(2a+3)-(a-1)2=______.13.如图,等边△ABC的边长为3cm,D,E分别是边AB,AC上的点,将△ADE沿直线DE折叠,使点A落在点A′处,且点A′在△ABC外部,则阴影部分图形的周长为______cm.14.如图,C,D和E,B分别是∠MAN的边AM和AN上的两点,且AC=AB,AD=AE,CE和BD相交于F点,给出下列结论:①△ABD≌△ACE;②△BFE≌△CFD;③F在∠MAN的平分线上.其中正确的是______.三、计算题(本大题共2小题,共20.0分)15.先化简÷+,当x取一个你喜欢的数值再计算代数式的值.(温馨提示:当心,分式要有意义)16.已知=,求(x-2y)2-(x-y)(x+y)-2y2的值.四、解答题(本大题共7小题,共70.0分)17.已知如图,四边形ABCD中,∠A与∠B互补,∠C=90°,DE⊥AB,E为垂足.若∠EDC=60°,求∠B、∠A及∠ADE的度数.18.观察下列各式探索发现规律:22-1=1×3;42-1=15=3×5;62-1=35=5×7;82-1=63=7×9,102-1=99=9×11……(1)按此规律写出第100个等式______.(2)用含正整数n的等式表示你所发现的规律为______.19.如图,点B、E、C、F在一条直线上,AB=DE,AC=DF,BE=CF.求证:∠A=∠D.20.如图,一块直径为a+b的圆形钢板,从中挖去直径分别为a与b的两个圆,求剩下的钢板的面积.21.如图,已知AB=AD,BC=DC,E是AC延长线上的点,求证:BE=DE.。
2020年新目标人教版英语八年级上册期末检测试题及答案三

期末测试卷(三)(满分:100分)Ⅰ. 单项填空(共15小题;每小题1分,满分15分)从每小题所给的A、B、C、D 四个选项中选出一个可以填入空白处的最佳选项。
1. A smile costs ,but gives so much. So we should learn to smile.A. somethingB. nothingC. anythingD. everything2. Tom the piano every day when he was in primary school.A. playsB. will playC. playedD. are playing3. —Did you go to the cinema to see Monkey King: Hero Is Back last night?—No, I go to the cinema. The tickets are too expensive.A.onlyB. nearlyC. stillD. hardly4. We wonder if our teachers to our graduating party next weekend. Ifthey ,we’ll be very happy.A.will come; will comeB. come; will comeC. will come; comeD. come; come5. —Which month has days in a year?—February.A. fewB. littleC. the leastD. the fewest6. —I’m sorry I’m calling you so late.—.A.No problemB. You’re welcomeC. That’s rightD. I’m all right7. Most parents their children to study hard and get a better job in the future.A.hopeB. planC. expectD. make8. It is one of the happiest things to an old friend.A.look forB. hear fromC. turn downD. make up9. We must work harder next term. There will be subjects, so we will havetime for each subject.A.less; moreB. more; fewerC. more; lessD. less; lessbus ______ ahead.10. —Carefully, Michael! There’s a schoolA.driveB. to driveC. droveD. driving11. —bottles of yogurt should I buy?—I think five bottles will be enough.A.How farB. How muchC. How longD. How many12. —Can you go to the supermarket this weekend?—. I have to help my parents with housework.A.Sure, I’d love toB. I’m afraid soC. I’m afraid notD. Sure, I love13. My family and I looking forward to my grandparents.A. am;visitB. are; visitC. am; visitingD. are; visiting14. —Is the child any better today?—I think so. His temperature seems now.A.highB. normalC. lowD. special15. Although Peter and Rick are brothers, they have little ____ common.A. forB. onC. inD. ofⅡ. 完形填空(共10小题;每小题2分,满分20分)阅读下列短文, 从每小题所给的A、B、C、D 四个选项中选出一个最佳选项。
人教部编版八年级上册语文期末测试题及答案含答案

人教部编版八年级上册语文期末测试题及答案含答案中国书法是中华民族文化的珍宝。
请将下面的格言抄写在方格内,要求正确、工整、整洁:古之立大事者,不惟有超世之才,亦必有坚韧不拔之志。
在下列词语中,加点字读音有误的一项是:惟妙惟肖(xiào)绮丽(qǐ)憎恨(zēng)两栖(qī)。
请根据具体的语境和拼音写出汉字:①父亲明明该高兴,却露出些gān gà(尴尬)的笑。
②历史、现实,在雨中融合了——融成一幅悲哀而美丽、真实而荒谬(miù)的画面。
③一个物种在新的环境中必然遵循物竞天择(jìng)的法则。
④有一个信客,年纪不小了,已经长途拜舍(báshè)了二三十年。
下列句子中加点词语使用有误的一项是:各级政府应该加大力度,因地制宜地发展地方农村经济,增加农民收入。
下列句子中说法错误的一项是:记叙文的主要表达方式是叙述和描写,但议论和抒情在记叙文中也经常运用。
仿照例句的句式,在后面的横线上再补写一个句子:你有权憧憬未来,但不应该忘记眼前的责任;你有权争取成功,但不应该以牺牲他人为代价:你有权享受自由,但不应该侵犯他人的权利。
默写:(1),江入大荒流。
(《渡荆门送别》)会当凌绝顶,(出自《望岳》)。
谁说人生没有再少的机会?门前的流水还能往西流!(出自《浣溪沙》)日暮乡关何处是?(出自《黄鹤楼》)出淤泥而不染”(出自XXX的《爱莲说》)何时没有月亮?哪里没有竹子和柏树?(出自《记承天寺夜游》)在《望洞庭湖赠张丞相》这首诗中,“气蒸XXX”这两句话,字句之间的力量十分强大,备受后人称赞。
日有所思,夜有所梦,铁马冰河入梦来”是爱国诗人XXX晚年时期的梦想,他不忘收复失地、统一祖国,这让人感到无比激动。
在《陋室铭》中,与“时人XXX中水,浅处无妨有卧龙”意思相近的句子是“有龙则灵”。
综合性研究(4分)本学期的名著导读向我们推荐了《朝花夕拾》、《骆驼祥子》和《钢铁是怎样炼成的》这三本书。
2020年人教版八年级语文上册期末试卷含答案

2020年人教版八年级语文上册期末试卷含答案满分:120分考试时间:120分钟一、语言的积累与运用。
(35分)1、选下列加点字注音有误的一项()A.萌.发(méng)携.带(xié)追溯.(shuò) 褶.皱(zhě)B.豁.然(huò)狩.猎(shòu)龟.裂(jūn) 缄.默(jiān)C.沟壑.(hè)山麓.(lù)钟鼎.(dǐng)浑浊.(zhuó)D.楔.形(xiē)羹匙.(chí)瑕疵.(cī)香蒲.(pú)3、下列句中加点成语使用不正确的一项是( )A.我们去采访那位老兵,当年惊心动魄....的战争场面,他还是记忆犹新。
B.恒大队锐不可当....,尤其是那几位年轻中国小将的表现,让人们看到了中国足球的未来。
C.冯小刚导演的电影《芳华》热播以来,广大市民对该节目的热衷程度可谓迫在..眉睫..。
D.站在左宗棠故居前,我不禁浮想联翩....,时空转换,似乎看见了这位伟人驰骋疆场的英姿。
4、下列句子没有语病的一项是()A.我们要及时解决并发现前进道路上遇到的问题。
B.小刚在众多参赛选手中脱颖而出的原因是他勤学苦练的结果。
C.纪念馆中大量增加的文物与史料,控诉了当年日本侵略者夺我疆土、戮我同胞。
D.美丽的海南岛是个风景优美的地方。
5、对下列句子使用修辞手法的判断正确的一项是()A.山河睡了而风景醒着,春天睡了而种子醒着。
(洛夫《湖南大雪——赠长沙李元洛》)(排比)B.风声在云外呼唤着,远山也在送青了。
(张晓风《到山中去》)(反复)C.五十岁上下的女人站在我面前,两手搭在髀间,没有系裙,张着两脚,正像一个画图仪器里细脚伶仃的圆规。
(鲁迅《故乡》)(比喻)D.在我们面前,天边远处仿佛有一片紫色的阴影从海里钻出来。
那就是哲尔赛岛了。
(莫泊桑《我的叔叔于勒))(夸张)6、下面横线上应填的句子排序恰当的一项是()七十年代,北方的平原上曾相继开展过平整土地运动和农田水利基本建设。
2020年人教版新目标八年级上册期末试题及答案 2

2020年人教版新目标八年级上册期末试题及答案一、单项选择(15小题,每小题1分,共15分)1. He gets up early but late.A. always; sometimesB. always; oftenC. often; alwaysD. usually; sometimes2. She is ________ than he is.A. much outgoingB. very more outgoingC. much more outgoingD.as ou tgoing3. My best friend enjoys ________ to music.A. listenB. listensC.to listenD. lis tening4. Lucy put a lot of _____ in _____ of tea.A. sugar, the two cupB. sugars, the two cupsC. sugar, the two cupsD. sugars, the cups5. —Li Lei, National Day is coming .Where will you go?—I decide _______ to Mount Tai.A. goB. will goC. to goD. going6. —You didn’t go to Shanghai last summer holidays, did you?—_______.A.Yes, I didn’tB. No, you didn’tC. No, you didD. No, I didn’t7. —What are you going to give your mother for her birthday?—I’m not sure. But I’ll buy her _______.A. somet hing specialB. anything specialC. special somethingD. special anything8. Our home is close ________ our school.A.toB. ofC. onD. about9. --- What do you usually do after school?--- I swim with my friends.A. readyB. ready toC. ready to doD. am ready to10. Mr. Wang didn't come, so Mrs. Wang .A. took him placeB. took his placeC. took of himD. became him11. Do you think _____ a sports meeting next month?A. is there going to beB. there is going to haveC. there is going to beD. there is going to leave12. You can read all kinds of books ____computers in 10 years.A.inB. onC.atD. of13. If people keep______the river, there will be no fish in the river.A. polluti ngB. polluteC. pollutedD.to pollute14. –Why not ____ some sugar ____ the coffee? - That sounds great.A. put, atB. add, toC. add, withD. add, /15. —Can I fill the box ________ my model cars?—I'm afraid not. It's full ________ my school things.A. with; withB. of; ofC. of; withD. with; of二、完形填空(10小题,每小题1分,共10分)The 2013 Talent Show in our school was a night to remember! It was agreat 16 Students, parents and teachers 17 , sang and playedinstruments. There were more than thirty 18 . Our English teacher Jason Cruise 19 an English song. He won the prize 20 the best performer. 21 a reporter from our school magazine interviewed him, he said that singingwas 22 important to him. The prize for the funniest act 23 to Paul Black, because he danced like a drunken (喝醉的) man without music. And his classmates said he was the 24 boy in the class.Many thanks to the parent and the student volunteers. They made this 25 show possible. Many thanks to all of the people who helped.16. A. success B. interest C. hobby D. dream17. A. said B. walked C. taught D. danced18. A. plays B. games C. acts D. lessons19. A. knew B. sang C. listened D. learned20. A. with B. of C. for D. on21. A. Before B. When C. If D. However22. A. anything B. nothing C. everything D. something23. A. wanted B. went C. asked D. had24. A. worst B. easiest C. funniest D. dullest25. A. talent B. talk C. fashion D. TV三、用所给词的正确形式填空。
人教版2020---2021学年度八年级数学(上)期末考试卷及答案(含两套题)

密 线学校 班级 姓名 学号密 封 线 内 不 得 答 题人教版2020—2021学年度上学期八年级数学(上)期末测试卷及答案(满分:150分 时间: 120分钟)第Ⅰ卷一、选择题(本大题共12小题,每小题4分,共48分.在每小题给出的四个选项中,只有一个选项是符合题目要求的) 1.若代数式4xx -有意义,则实数x 的取值范围是( ) A .x =0 B .x =4C .x ≠0D .x ≠42.随着微电子制造技术的不断进步,电子元件的尺寸大幅度缩小,在芯片上某种电子元件大约只占0.0000007平方毫米,将数字0.0000007用科学记数法可以表示为( ) A .6710-⨯ B .60.710-⨯C .7710-⨯D .87010-⨯3.下列式子,成立的是( ) A .a 2·a 3=a 6 B .(a 2)3=a 5C .a –1=–aD .(–a +b )(–a –b )=a 2–b 24.如果把分式xyx y+中的x 和y 都扩大2倍,那么分式的值( )A .扩大4倍B .扩大2倍C .不变D .缩小2倍5.若等腰三角形中有两边长分别为3和7,则这个三角形的周长为( ) A .13 B .13或17C .10D .176.在平面直角坐标系中,将点A (–1,2)向右平移4个单位长度得到点B ,则点B 关于y 轴的对称点B ′的坐标为( ) A .(–3,2) B .(3,–2) C .(3,2)D .(2,–3)7.如图,在△ABC 和△BDE 中,点C在边BD 上,边AC 交边BE 于点F ,若AC =BD ,AB =ED ,BC =BE ,则∠ACB 等于( )A .∠DB .∠EC .∠EBDD .∠ABF8.点O 在ABC △(非等边三角形)内,且OA OB OC ==,则点O为( )A .ABC △的三条角平分线的交点题号一 二 三 总分 得分B .ABC △的三条高线的交点C .ABC △的三条边的垂直平分线的交点D .ABC △的三条边上的中线的交点9.如图,AE ∥DF ,AE =DF ,则添加下列条件还不能使△EAC≌△FDB 的为( )A .AB =CD B .CE ∥BFC .∠E =∠FD .CE =BF10.如图,AD 是△ABC 的角平分线,DE ⊥AB 于E ,△ABC 的面积为10,AB =6,DE =2,则AC 的长是( )A .4B .4.5C .4.8D .5 11.从3-,2-,1-,32-,1,3这六个数中,随机抽取一个数,记为a .关于x 的方程211x ax +=-的解是正数,那么这6个数中所有满足条件的a 的值有( ) A .3个B .2个C .1个D .4个12.如图,在等边三角形ABC 中,BC 边上的中线AD =6,是AD 上的一个动点,F 是边AB 上的一个动点,在点F 运动的过程中,EB +EF 的最小值是A .5B .6C .7D .8第Ⅱ卷二、填空题(本大题共6小题,每小题4分,共24分)13.若23a b =,则a b b -=__________.14.若3a b +=,1ab =,则22ab +=__________.15.若一个多边形的内角和是900º,则这个多边形是__________边形.16.如图,依据尺规作图的痕迹,计算α∠=__________°.17.已知ABC ∆中,它的三边长a 、b 、c 都是正整数,其中a 是最长边,且满足22106340a b a b +--+=,则符合条件的c密线学校 班级 姓名 学号密 封 线 内 不 得 答 题值为__________.18.如图,∠ABC =∠ACB ,AD 、BD 、CD 分别平分△ABC 的外角∠EAC 、内角∠ABC 、外角∠ACF .以下结论:①AD∥BC ;②∠ACB =2∠ADB ;③∠ADC =90°−12∠ABC ;④BD 平分∠ADC ;⑤∠BDC =12∠BAC .其中正确的结论有__________(填序号)三、解答题(本大题共9小题,共78分.解答应写出文字说明、证明过程或演算步骤) 19.(本小题满分6分) (1)解方程:22+11x x x x+=+;(2)解方程:2227361x x x x x -=+--. 20.(本小题满分6分)(1)因式分解22(2)(22)1a ab b a b -++-++;(2)先化简,再求值24512(1)(),11a a a a a a-+-÷----其中1a =-. 21.(本小题满分6分)如图,点B 、C 、D 、E 在同一条直线上,已知AB =FC ,AD =FE ,BC =DE . (1)求证:△ABD ≌△FCE .(2)AB 与FC 的位置关系是_________(请直接写出结论)22.(本小题满分8分)如图,在△ABC 中,AB =AC ,∠A =36°,AC 的垂直平分线交AB 于E ,D 为垂足,连接EC . (1)求∠ECD 的度数; (2)若CE =5,求BC 的长.23.(本小题满分8分)超市用2500元购进某品牌苹果,以每千克8元的单价试销.销售良好,超市又安排4500元补货.补货进价比上次每千克少0.5元,数量是上次的2倍.(1)求两次进货的单价分别是多少元.(2)当售出大部分后,余下200千克按7.5折售完,求两次销售苹果的毛利.24.(本小题满分10分)如图,△ABC 中,∠BAC =90°,AD⊥BC ,垂足为D .(1)求作∠ABC 的平分线,分别交AD ,AC 于E ,F 两点;(要求:尺规作图,保留作图痕迹,不写作法)(2)证明:AE=AF.25.(本小题满分10分)如图,网格中有格点△ABC与△DEF.(1)△ABC与△DEF是否全等?(不说理由.)(2)△ABC与△DEF是否成轴对称?(不说理由)(3)若△ABC与△DEF成轴对称,请画出它的对称轴l.并在直线l上画出点P,使PA+PC最小.26.(本小题满分12分)探究下面的问题:(1)如图甲,在边长为a的正方形中去掉一个边长为b的小正方形(a>b),把余下的部分剪拼成如图乙的一个长方形,通过计算两个图形(阴影部分)的面积,验证了一个等式,这个等式是________(用式子表示),即乘法公式中的___________公式.(2)运用你所得到的公式计算:①10.7×9.3;②(23)(23)x y z x y z+---.27.(本小题满分12分)在△ABC中,∠BAC=100°,∠∠ACB,点D在直线BC上运动(不与点B、C点E在射线AC上运动,且∠ADE=∠AED,设∠DAC=(1)如图①,当点D在边BC上时,且n=36°BAD=__________,∠CDE=__________;(2)如图②,当点D运动到点B变,请猜想∠BAD和∠CDE(3)当点D运动到点C的右侧时,其他条件不变,∠和∠CDE还满足(2)中的数量关系吗?请画出图形,明理由.密 线学校 班级 姓名 学号密 封 线 内 不 得 答 题参考答案一1 2 3 4 5 6 7 8 9 10 11 12 DCDBDACCDABB二、13.【答案】3-【解析】∵23a b =,∴设a =2k ,b =3k (k ≠0),则23133a b k k b k --==-, 故答案为:13-.14.【答案】7【解析】∵a +b =3,ab =1,∴22a b +=(a +b )2–2ab =9–2=7;故答案为7. 15.【答案】七【解析】设这个多边形是n 边形,根据题意得,()2180900n -⋅︒=︒,解得7n =.故答案为:7. 16.【答案】56【解析】如图,∵四边形ABCD 是长方形,∴AD ∥BC ,∴∠DAC =∠ACB =68°, ∵由作法可知,AF 是∠DAC 的平分线,∴∠EAF =12∠DAC =34°,∵由作法可知,EF 是线段AC 的垂直平分线,∴∠AEF =90°, ∴∠AFE =90°−34°=56°,∴∠α=56°.故答案为:56.17.【答案】6或7【解析】a 2+b 2–10a –6b +34=0, a 2–10a +25+b 2–6b +9=0,(a –5)2+(b –3)2=0, 则a –5=0,b –3=0,解得,a =5,b =3, 则5–3<c <3+5,即2<c <8,∴△ABC 的最大边c 的值为6或7, 故答案为:6或7. 18.【答案】①②③⑤【解析】∵AD 平分∠EAC ,∴∠EAC =2∠EAD , ∵∠EAC =∠ABC +∠ACB ,∠ABC =∠ACB ,∴∠EAD =∠ABC ,∴AD ∥BC ,∴①正确; ∵AD ∥BC ,∴∠ADB =∠DBC ,∵BD 平分∠ABC ,∠ABC =∠ACB ,∴∠ABC =∠ACB =2∠DBC ,∴∠ACB =2∠ADB ,∴②正确;∵AD平分∠EAC,CD平分∠ACF,∴∠DAC=12∠EAC,∠DCA=12∠ACF,∵∠EAC=∠ABC+∠ACB,∠ACF=∠ABC+∠BAC,∠ABC+∠ACB+∠BAC=180°,∴∠ADC=180°−(∠DAC+∠ACD)=180°−12(∠EAC+∠ACF)=180°−12(∠ABC+∠ACB+∠ABC+∠BAC)=180°−12(180°+∠ABC)=90°−12∠ABC,∴③正确;∵BD平分∠ABC,∴∠ABD=∠DBC,∵∠ADB=∠DBC,∠ADC=90°−12∠ABC,∴∠ADB不一定等于∠CDB,∴④错误;∵∠ACF=2∠DCF,∠ACF=∠BAC+∠ABC,∠ABC=2∠DBC,∠DCF=∠DBC+∠BDC,∴∠BAC=2∠BDC,∴∠BDC=12∠BAC,∴⑤正确;故答案为:①②③⑤.三、19.【解析】(1)方程两边都乘x(x+1),得x2+x2+x=2(x+1)2,解得:x=−23,检验:当x=−23时,x(x+1)≠0,∴x=−23是原方程的解.(3分)(2)去分母得:7x−7+3x+3=6x,解得:x=1,经检验x=1是增根,分式方程无解.(6分)20.【解析】(1)原式=(a2–2ab+b2)–(2a–2b)+1=(a–b)2–2(a–b)+1=(a–b–1)2.(3分)(2)原式()()()211452(2)111a a a a aa a a a+--+--=÷=---•()12a aa-=-a(a–2当a=–1时,原式=–1×(–1–2)=3.(6分)21.【解析】(1)∵BC=DE,∴BC+CD=DE+CD,即BD=CE.在△ABD和△FCE中,AB FCAD FEBD CE=⎧⎪=⎨⎪=⎩,∴△ABD≌△FCE(SSS).(4分)(2)AB∥FC.(6分)由(1)可知△ABD≌△FCE,∴∠B=∠FCE(全等三角形的对应角相等),∴AB∥FC(同位角相等,两直线平行).22.【解析】(1)∵DE垂直平分AC,∠A=36°,∴CE=AE,∴∠ECD=∠A=36°;(4分)(2)∵AB=AC,∠A=36°,∴∠B=∠ACB=72°,密线学校 班级 姓名 学号密 封 线 内 不 得 答 题∴∠BEC =∠A +∠ECD =72°,∴∠BEC =∠B ,∴BC =EC =5.(8分)23.【解析】(1)设第一次进货的单价是x 元,则第二次进货的单价是(0.5)x -元,根据题意,得2500450020.5x x ⨯=-,解得5x =. 经检验:5x =是原方程的解.第二次进货的单价是:50.5 4.5()-=元.答:第一次进货的单价是5元,第二次进货的单价是4.5元.(4分)(2)两次销售苹果的毛利:25004500200820080.752500450046005 4.5⎛⎫+-⨯+⨯⨯--=⎪⎝⎭(元). 答:两次销售苹果的毛利为4600元.(8分) 24.【解析】(1)如图所示,射线BF 即为所求:(4分)(2)证明:∵AD ⊥BC ,∴∠ADB =90°,∴∠BED +∠EBD =90°,∵∠BAC =90°,∴∠AFE +∠ABF =90°,(7分) ∵∠EBD =∠ABF ,∴∠AFE =∠BED ,∵∠AEF =∠BED ,∴∠AEF =∠AFE ,∴AE =AF .(10分) 25.【解析】(1)全等.(3分)根据坐标系可以看出AB DEBC EFAC DF =⎧⎪=⎨⎪=⎩,∴△ABC ≅△DEF ;(2)成轴对称.(6分)根据坐标系可以看出△ABC 与△DEF 关于直线l 成轴对称; (3)如图所示:点P 即为所求.(10分)26.【解析】(1)a 2–b 2=(a +b )(a −b );平方差.(6分)由图知:大正方形减小正方形剩下的部分面积为a 2–b 2; 拼成的长方形的面积:(a +b )×(a −b ),所以得出:a 2–b 2=(a +b )(a −b );故答案为:a 2–b 2=(a +b )(a −b );平方差. (2)①原式=(10+0.7)×(10–0.7) =102–0.72 =100–0.49 =99.51.(9分)②原式=(x –3z +2y )(x –3z –2y ) =(x –3z )2–(2y )2 =x 2–6xz +9z 2–4y 2.(12分)27.【解析】(1)∠BAD =∠BAC –∠DAC =100°–36°=64°.∵在△ABC 中,∠BAC =100°,∠ABC =∠ACB , ∴∠ABC =∠ACB =40°,∴∠ADC =∠ABC +∠BAD =40°+64°=104°. ∵∠DAC =36°,∠ADE =∠AED , ∴∠ADE =∠AED =72°,∴∠CDE =∠ADC –∠ADE =104°–72°=32°. 故答案为64°,32°;(4分)(2)∠BAD =2∠CDE ,理由如下:(5分) 如图②,在△ABC 中,∠BAC =100°, ∴∠ABC =∠ACB =40°. 在△ADE 中,∠DAC =n ,∴∠ADE =∠AED =1802n︒-.(6分)∵∠ACB =∠CDE +∠AED ,∴∠CDE =∠ACB –∠AED =40°–1802n ︒-=1002n -︒. ∵∠BAC =100°,∠DAC =n , ∴∠BAD =n –100°,∴∠BAD =2∠CDE ;(8分) (3)∠BAD =2∠CDE ,理由如下: 如图③,在△ABC 中,∠BAC =100°,∴∠ABC =∠ACB =40°,∴∠ACD =140°.(9分) 在△ADE 中,∠DAC =n , ∴∠ADE =∠AED =1802n︒-.(10分)∵∠ACD =∠CDE +∠AED , ∴∠CDE =∠ACD –∠AED =140°–1802n ︒-=1002n︒+. ∵∠BAC =100°,∠DAC =n , ∴∠BAD =100°+n , ∴∠BAD =2∠CDE .(12分)密线学校 班级 姓名 学号密 封 线 内 不 得 答 题人教版2020—2021学年度上学期八年级数学(上)期末测试卷及答案(满分:150分 时间: 120分钟)第Ⅰ卷一、选择题(本大题共12小题,每小题4分,共48分.在每小题给出的四个选项中,只有一个选项是符合题目要求的) 1.下列图形中,是轴对称图形的是( )A .B .C .D .2.下列分式中,属于最简分式的是( )A .1113xB .221xx +C .211x x +-D .11x x --3.以下列各组线段为边,能组成三角形的是( ) A .2cm ,5cm ,8cm B .3cm ,3cm ,6cm C .3cm ,4cm ,5cmD .1cm ,2cm ,3cm4.如果一个多边形的每一个内角都是108°,那么这个多边形是( ) A .五边形 B .六边形C .七边形D .八边形5.下列运算正确的是( ) A .236a a a ⋅= B .220a a ÷=C .2353()a b a b =D .752a a a ÷=6.下列各式分解因式正确的是( ) A .()()2919191x x x -=+- B .()()422111a a a -=+- C .()()228199a b a b a b --=--+D .()()()32a ab a a b a b -+=-+-7.已知ab ≠0,则坐标平面内四个点A (a ,b ),B (a ,–b ),C (–a ,b ),D (–a ,–b )中关于y 轴对称的是( ) A .A 与B ,C 与DB .A 与D ,B 与C C .A 与C ,B 与DD .A 与B ,B 与C8.如图,△ABC ≌△ADE ,若∠E =70°,∠D =30°,∠CAD =35°,则∠BAD 的度数为( )A .40°B .45°C .50°D .55°9.光明家具厂生产一批学生课椅,计划在30天内完成并交付题号一 二 三 总分 得分不得答题使用.若每天多生产100把,则23天完成且还多生产200把.设原计划每天生产x把,根据题意,可列分式方程为( )A.3020023100xx+=+B.3020023100xx-=+C.3020023100xx+=-D.3020023100xx-=-10.解关于x的方程6155x mx x-+=--(其中m为常数)产生增根,则常数m的值等于( )A.–2 B.2C.–1 D.111.如图,△ABC中,AB的垂直平分线交AC于D,如果AC=5cm,BC=4cm,那么△DBC的周长是( )A.6cm B.7cmC.8cm D.9cm12.如图,BP平分ABC∠交CD于点F,DP平分ADC∠交AB于点E,若40A∠=︒,38P∠=︒,则C∠的度数为( )A.36︒B.39︒C.38︒D.40︒第Ⅱ卷二、填空题(本大题共6小题,每小题4分,共24分)13.一种细菌的半径是0.00003厘米,数据0.00003数法表示为_________.14.计算:2232aa a a---=_________.15.若分式33xx--的值为零,则x=_________.16.如图,ABC∆中,90C∠=︒,30A∠=︒,AB的垂直平分线交于D,交AB于E,2CD=,则AC=_________.17.在等腰ABC∆中,一腰上的高与另一腰的夹角为26︒角的度数为__________.18.如图,在△ABC中,AB=AC,∠BAC=50°,∠BAC线与AB的垂直平分线交于点O,将∠C沿EF(E在上,F在AC上)折叠,点C与点O恰好重合,则∠为________度.密线学校 班级 姓名 学号密 封 线 内 不 得 答 题三、解答题(本大题共9小题,共78分.解答应写出文字说明、证明过程或演算步骤) 19.(本小题满分6分)计算:(1)()()22x y x y x ---;(2)2344(1)11x x x x x ++-+÷++.20.(本小题满分6分)因式分解:(1)4x 2–16;(2)(x +y )2–10(x +y )+25.21.(本小题满分6分)如图,AD 与BC 交于E ,∠1=∠2=∠3,∠4=∠5.求证:BD =E C .22.(本小题满分8分)如图,五边形ABCDE 的内角都相等,EF 平分∠AED .求证:EF ⊥BC .23.(本小题满分8分)如图,△ABC 的顶点均在格点上.(1)分别写出点A ,点B ,点C 的坐标.(2)若△A 'B 'C '与△ABC 关于y 轴对称,在图中画出△A 'B 'C ',并写出相应顶点的坐标.24.(本小题满分10分)如图,ABC ∆与DCB ∆中,AC 与BD 交于点E ,且A D ∠=∠,AB DC =.(1)求证:ABC DCB ∆≅∆;(2)当50AEB ∠=︒,求EBC ∠的度数.25.(本小题满分10分)嘉嘉同学动手剪了如图①所示的正方形与长方形卡片若干张.(1)他用1张1号、1张2号和2张3号卡片拼出一个新的图形(如图②).根据这个图形的面积关系写出一个你所熟悉的乘法公式,这个乘法公式是________. (2)如果要拼成一个长为(a +2b ),宽为(a +b )的大长方形,则需要1号卡片________张,2号卡片________张,3号卡片________张.26.(本小题满分12分)市区某中学美化校园招标时,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30天;若由甲队先做10天,剩下的工程由甲、乙合做12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35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该工程省钱,还是由甲乙两队全程合作完成该工程省钱?27.(本小题满分12分)如图,在ABC ∆中,已知45ABC ∠=,过点C 作CD AB ⊥于点D ,过点B 作BM AC ⊥于点M ,连接MD ,密线学校 班级 姓名 学号密 封 线 内 不 得 答 题故答案为:11a --.15.【答案】–3【解析】依题意,得|x |–3=0且x –3≠0,解得x =–3.故答案是:–3.16.【答案】6【解析】连接BD ,∵在△ABC 中,∠C =90°,∠A =30°,∴∠ABC =60°, ∵AB 的垂直平分线交AC 于D ,交AB 于E ,∴AD =BD ,DE ⊥AB ,∴∠ABD =∠A =30°,∴∠DBC =30°, ∵CD =2,∴BD =2CD =4,∴AD =4,∴AC =6.17.【答案】58°或32°【解析】①如图①,∵AB =AC ,∠ABD =26°,BD ⊥AC ,∴∠A =64°,∴∠ABC =∠C =(180°–64°)÷2=58°;②如图②,∵AB =AC ,∠ABD =26°,BD ⊥AC , ∴∠BAC =26°+90°=116°,∴∠ABC =∠C =(180°–116°)÷2=32°,故答案为:58°或32°.18.【答案】50°【解析】如图,连接OB ,OC ,∵∠BAC =50°,AO 为∠BAC 的平分线,∴∠BAO =12∠BAC =12×50°=25°.又∵AB =AC ,∴∠ABC =∠ACB =65°.∵DO 是AB 的垂直平分线,∴OA =OB ,∴∠ABO =∠BAO =25°,∴∠OBC =∠ABC –∠ABO =65°–25°=40°.∵AO 为∠BAC 的平分线,AB =AC ,∴直线AO 垂直平分BC ,∴OB =OC ,∴∠OCB =∠OBC =40°,∵将∠C 沿EF (E 在BC 上,F 在AC 上)折叠,点C 与点O 恰好重合,题∴OE =CE .∴∠COE =∠OCB =40°;在△OCE 中,∠OEC =180°–∠COE –∠OCB =180°–40°–40°=100°,∴∠CEF =12∠CEO =50°.故答案为:50°. 三、19.【解析】(1)原式=22222x xy y xy x -+-+=2233x xy y -+;(3分)(2)原式=231x+11(2)x x x x --+⨯++()(1)=223111(2)x x x x -++⨯++=2(2)(2)11(2)x x x x x -++⨯++=22xx -+.(6分)20.【解析】(1)4x 2–16=4(x 2–4)=4(x +2)(x –2);(3分) (2)(x +y )2–10(x +y )+25 =(x +y –5)2.(6分) 21.【解析】1=2314,43AEC ABD ∠∠=∠∠=∠+∠∠=∠+∠,,∴AEC ABD ∠=∠.(2分)45∠=∠,AB AE =∴.在ABD △和AEC 中1=2AB AE ABD AEC ∠∠⎧⎪=⎨⎪∠=∠⎩,(4分)∴ABD AEC ≅.∴BD =EC .(6分)22.【解析】∵五边形ABCDE 的内角都相等,∴∠C =∠D =∠AED =180°×(5–2)÷5=108°,(2分)又EF 平分∠AED , ∴°1542FED AED ∠=∠=,(4分)∴在四边形DEFC 中360EFC D C FED ︒∠=-∠-∠-∠=90°,∴EF ⊥BC .(8分)23.【解析】(1)点A (3,4),B (1,2),C (5,1(3分)(2)如图所示,△A 'B 'C '即为所求,(5分)点A ′(﹣3,4),B ′(﹣1,2),C ′(﹣5,1).(8密 线学校 班级 姓名 学号密 封 线 内 不 得 答 题24.【解析】(1)在△ABE 和△DCE中,A D AEB DEC AB DC ∠=∠⎧⎪∠=∠⎨⎪=⎩,∴△ABE ≌△DCE (AAS ),∴BE =EC ,∠ABE =∠DCE ,(4分)∴∠EBC =∠ECB ,∵∠EBC +∠ABE =∠ECB +∠DCE ,∴∠ABC =∠DBC ,(6分)在△ABC 和△DCB中,A DAB DC ABC DBC ∠=∠⎧⎪=⎨⎪∠=∠⎩,∴△ABC ≌△DCB (ASA );(8分) (2)∵∠AEB =50°,∴∠EBC +∠ECB =50°, ∵∠EBC =∠ECB ,∴∠EBC =25°.(10分)25.【解析】(1)这个乘法公式是(a +b )2=a 2+2ab +b 2,故答案为:(a +b )2=a 2+2ab +b 2;(4分)(2)要拼成一个长为(a +2b ),宽为(a +b )的大长方形,根据(a +2b )(a +b )=a 2+3ab +2b 2,则需要1号卡片1张,2号卡片2张,3号卡片3张.故答案为:1;2;3.(10分)26.【解析】(1)设乙队单独完成这项工程需要x 天,依题意,得:101212130x ++=,解得x =45,经检验,x =45是所列分式方程的解,且符合题意. 答:乙队单独完成这项工程需要45天.(6分) (2)甲乙两队全程合作需要1÷(11+3045)=18(天),甲队单独完成该工程所需费用为3.5×30=105(万元); ∵乙队单独完成该工程需要45天,超过35天的工期, ∴不能由乙队单独完成该项工程;甲、乙两队全程合作完成该工程所需费用为(3.5+2)×18=99(万元).∵105>99,∴在不超过计划天数的前提下,由甲、乙两队全程合作完成该工程省钱.(12分) 27.【解析】(1)∵45ABC ∠=,CD AB ⊥,∴45ABC DCB ∠=∠=,∴BD DC =,∵90BDC MDN ∠=∠=,∴BDN CDM ∠=∠,(3分) ∵CD AB ⊥,BM AC ⊥, ∴90ABM A ACD ∠=-∠=∠,在DBN ∆和DCM ∆中,BDN CDM BD DCDBN DCM ∠=∠⎧⎪=⎨⎪∠=∠⎩,∴DBN ∆≌DCM ∆;(6分) (2)结论:NEME CM ,证明:由(1)DBN ∆≌DCM ∆可得DM DN =. 作DF MN ⊥于点F , 又ND MD ⊥,∴DF FN =,在DEF ∆和CEM ∆中,DEF CEM DFE CMEDE EC ∠=∠⎧⎪∠=∠⎨⎪=⎩,∴DEF ∆≌CEM ∆,∴EF EM =,DF CM =,∴CM DF FN NE FE NE ME ===-=-.(12分)。
人教版2020-2021学年八年级上册期末检测题及答案(含三套题)

人教版2020--2021学年度第一学期八年级数学期末检测题及答案题号一二三总分得分时间:100分钟满分:100分一、选择题(共10小题,每小题3分,满分30分)1.在平面直角坐标系中,点(﹣1,﹣2)所在的象限是()A.第一象限B.第二象限C.第三象限D.第四象限2.我国主要银行的商标设计基本上都融入了中国古代钱币的图案,如图是我国四个银行的商标图案,其中是轴对称图形的有()A.①②③B.①②④C.①③④D.②③④3.在下列长度的四根木棒中,能与4cm、9cm长的两根木棒钉成一个三角形的是()A.4cm B.5cm C.9cm D.13cm4.点A(﹣3,2)关于x轴的对称点A′的坐标为()A.(﹣3,﹣2)B.(3,2)C.(3,﹣2)D.(2,﹣3)5.等腰三角形一腰上的高与另一腰的夹角为30°,则顶角的度数为()A.60°B.120°C.60°或150°D.60°或120°6.已知P1(﹣3,y1),P2(2,y2)是一次函数y=2x﹣b的图象上的两个点,则y1,y2的大小关系是()A.y1<y2B.y1=y2C.y1>y2D.不能确定7.如图,已知∠ADB=∠ADC,欲证△ABD≌△ACD,还必须从下列选项中选一个补充条件,其中错误的选项是()A.∠BAD=∠CAD B.AB=AC C.BD=CD D.∠B=∠C8.如图,在△ABC中,∠ACB=90°,BE平分∠ABC,ED⊥AB于D.如果∠A=30°,AE=6cm,那么CE等于()A.cm B.2cm C.3cm D.4cm9.如图,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10.如图,△ABC中,P、Q分别是BC、AC上的点,作PR⊥AB,PS⊥AC,垂足分别是R、S,若AQ=PQ,PR=PS,下面三个结论:①AS=AR②QP∥AR③△BRP≌△QSP.其中正确的是()A.①③B.②③C.①②D.①②③二、填空题(每小题3分,共24分)11.函数y=中,自变量x的取值范围是.12.将点(1,2)向左平移1个单位,再向下平移2个单位后得到对应点的坐标是.13.如图,△ABC中,DE是AC的垂直平分线,AE=5,△ABC的周长是30,则△ABD的周长是.14.小明不慎将一块三角形的玻璃摔碎成如图所示的四块(即图中标有1、2、3、4的四块),你认为将其中的哪一块带去,就能配一块与原来一样大小的三角形?应该带第块.15.如图,线段AD与BC相交于点O,连接AB、CD,且OB=OD,要使△AOB≌△COD,应添加一个条件是(只填一个即可).16.写一个图象交y轴于点(0,﹣3),且y随x的增大而增大的一次函数关系式.17.如图,把两根钢条的中点连在一起,可以做成一个测量工件内槽宽的工具(卡钳).在图中,只要量出CD的长,就能求出工件内槽的宽,依据是.18.如图,已知△ABC的角平分线CD交AB于D,DE∥BC交AC于E,若DE=3,AE=4,则AC=.三.解答题(46分)19.(6分)△ABC在平面直角坐标系中的位置如图所示.(1)作出△ABC关于y轴对称的△A1B1C1;并写出△A1B1C1各顶点的坐标;(2)将△ABC向右平移6个单位,再向下平移1个单位:作出平移后的△A2B2C220.(6分)已知:如图,∠1=∠2,∠C=∠D.求证:△ABC≌△ABD.21.(8分)为了保护学生的视力,课桌的高度m与椅子的高度xcm(不含靠背)都是按y是x的一次函数关系配套设计的,如表列出了两套符合条件课桌椅的高度:第一套第二套40.038.0椅子高度xcm75.070.2课桌高度ycm(1)请求出y与x的函数关系式(不要求写出x的取值范围);(2)现有一把高42.0cm的椅子和一张高78.2cm的课桌,它们是否配套?请通过计算说明理由.22.(8分)“佳园工艺店”打算制作一批有两边长分别是7分米,3分米,第三边长为奇数(单位:分米)的不同规格的三角形木框.(1)要制作满足上述条件的三角形木框共有种.(2)若每种规格的三角形木框只制作一个,制作这种木框的木条的售价为8元╱分米,问至少需要多少钱购买材料?(忽略接头)23.(8分)如图,AC是某座大桥的一部分,DC部分因受台风侵袭已垮塌,为了修补这座大桥,需要对DC的长进行测量,测量人员在没有垮塌的桥上选取两点A和D,在C处对岸立着的桥墩上选取一点B(BC⊥AC),然后测得∠A=30°,∠ADB=120°,AD=60m.求DC的长.24.(10分)已知:如图,AB,CD相交于点O,AC∥DB,OC=OD,E,F为AB 上两点,且AE=BF.求证:CE∥DF.人教版2020--2021学年度第一学期八年级数学期末检测题及答案题号一二三总分得分时间:100分钟满分:100分一、选择题(每题3分,共30分)1.(3分)在实数范围内,有意义,则x的取值范围是()A.x≥1 B.x≤1 C.x>1 D.x<12.(3分)在3.1415926,,,中,无理数有()A.1个B.2个C.3个D.4个3.(3分)既是轴对称图形又是中心对称图形的是()A.直角三角形B.等边三角形C.等腰直角三角形D.圆4.(3分)下列根式是最简二次根式的是()A.B.C.D.5.(3分)若实数x,y满足|x﹣4|+=0,则以x,y的值为边长的等腰三角形的周长为()A.20 B.16 C.20或16 D.126.(3分)若分式的值为0,则x的值为()A.﹣1 B.1 C.±1 D.07.(3分)使两个直角三角形全等的条件是()A.一个锐角对应相等B.两个锐角对应相等C.一条边对应相等D.两条边对应相等8.(3分)如图,OC平分∠MON,P为OC上一点,PA⊥OM,PB⊥ON,垂足分别为A、B,连接AB,得到以下结论:(1)PA=PB;(2)OA=OB;(3)OP与AB互相垂直平分;(4)OP平分∠APB,正确的个数是()A.1 B.2 C.3 D.49.(3分)如图,△ABC中,∠A=50°,∠C=60°,DE垂直平分AB,则∠DBC的度数为()A.10°B.20°C.30°D.40°10.(3分)如图,在等边三角形ABC中,BD=CE,将线段AE沿AC翻折,得到线段AM,连结EM交AC于点N,连结DM、CM以下说法:①AD=AE=AM,②∠ECA=∠MCA,③CN=EC,④AD=DM中,正确的是()A.①②B.①②③C.①②③D.①②③④二、填空题(每空2分,共20分)11.(4分)化简:÷= ; = .12.(2分)如图,AD为Rt∠ABC的角平分线,∠B=90°,AC=5,DB=2,则D到AC距离为.13.(2分)正方形的边长为a,它的面积与长为4cm、宽为12cm的长方形的面积相等,则a= cm.14.(2分)已知=2,则= .15.(2分)如图,△ABC中,AB=8,AC=6,BC=5,∠ABC与∠ACB的平分线相交于点O,过O点作DE∥BC,则△ADE的周长为.16.(2分)某人骑自行车比步行每小时多走8千米,如果他步行12千米所用时间与骑车行36千米所用时间相等,那么他的步行速度为千米/小时.17.(2分)如图,Rt△ABC中,∠B=90°,AB=8cm,BC=6cm,D点从A出发以每秒1cm的速度向B点运动,当D点运动到AC的中垂线上时,运动时间为秒.18.(2分)如图,△ABC中,AB=AC=13,BC=10,AD⊥BC,BE⊥AC,P为AD上一动点,则PE+PC的最小值为.19.(2分)如图,数轴上A点表示数7,B点表示数5,C为OB上一点,当以OC、CB、BA三条线段为边,可以围成等腰三角形时,C点表示数.三、解答题(共50分)20.(9分)计算(1)先化简,再求值+÷,其中a=+1.(2)已知x=2﹣,求代数式(7+4)x2+(2+)x+的值.21.(12分)如图,8×8网格中,每个小正方形边长为1.(1)分别画出△ABC绕O点逆时针旋转90°所得△A1B1C1及△ABC关于O点的中心对称图形;(2)连结A2B,BB2,判断△A2B2B形状并证明;(3)证明C2不在线段A2B上.22.(10分)我们知道定理“直角三角形斜边上的中线等于斜边的一半”,这个定理的逆命题也是真命题.(1)这个定理的逆命题是;(2)下面我们来证明这个逆命题:已知:如图1,CD是△ABC的中线,CD=AB求证:△ABC为直角三角形.(3)如图2已知线段AB和直线l,点C是直线l上一点,若△ABC为直角三角形,请你用圆规和没有刻度的直尺确定点C位置.23.(9分)锐角△ABC中,E、D分别为AB,AC上一点,BD与CE相交于点M,BD=CE.(1)若∠BDC=∠CEB=90°,如图①①求证:△BDC≌△CEB;②求证:AM平分∠BAC.(2)若∠BDC≠90°,∠CEB≠90°,AB=AC,当BD=CE时,AM不一定平分∠BAC,请你在图②中尺规画图举例,并直接写出当AM不平分∠BAC时,∠BDC与∠CEB 的关系.24.(10分)取一张长方形纸片ABCD(如图①),AB=8,BC=a.(1)当a=16时,按下列步骤操作①将图①纸片对折,使较长的两边BC,AD重合,折痕为EF,再打开纸片,如图②.②再折叠,使点A落在EF上的点G处,折痕为BH,如图③③连接AG,BG.请证明△ABG是等边三角形.(2)小明认为当a<8时,折不出边长为8的等边三角形.你认为他的说法正确吗?若不正确请通过计算说明,a满足什么条件时能折出一个边长为8的等边三角形?(3)当a足够大时,请你利用折纸,折出一个面积最大的等边三角形,并写出折法.参考答案一、选择题1.A.2.A.3.D.4.B. 5.A.6.C.7.D.8.C.9.B.10.D.二、填空题11.2,2. 12.2 13.4.14.﹣1. 15.14. 16.4. 17.18. 19.2或2.5或3.三、解答题20.解:(1)原式=+•=+=,当a=+1时,原式==1+;(2)∵x=2﹣,∴x2=(2﹣)2=7﹣4,∴(7+4)x2+(2+)x+=(7+4)(7﹣4)+(2+)(2﹣)+ =1+1+=2+.21.(1)解:如图,△A1B1C1和△A2B2C2为所作;(2)解:△A2B2B为直角三角形.理由如下:∵B2B2=22+42=20,A2B22=22+12=5,A2B2=32+42=25,∴B2B2+A2B22=A2B2,∴△A2B2B为直角三角形;(3)证明:∵A2C2==,BC2==,A2B=5,∴A2C2+BC2≠A2B,∴C2不在线段A2B上22.解:(1)∵“直角三角形斜边上的中线等于斜边的一半”,∴它逆命题是:如果一个三角形一边上的中线等于这条边的一半,那么这个三角形是直角三角形,故答案为:如果一个三角形一边上的中线等于这条边的一半,那么这个三角形是直角三角形;(2)如图,∵CD是△ABC的中线,∴AD=BD=AB,∵CD=AB,∴AD=CD=BD,∴∠A=∠1,∠B=∠2,在△ABC中,∠A+∠B+∠1+∠2=180°,∴∠1+∠2+∠1+∠2=180°,∴∠1+∠2=90°,∴∠ACB=90°,∴△ABC为直角三角形;(3)如图2所示,△ABC和△ABC'为所求作的图形,23.(1)①证明:在Rt△ADB和Rt△AEC中,,∴Rt△ADB≌Rt△AEC;②证明:∵Rt△ADB≌Rt△AEC,∴∠ABD=∠ACE,∵AB=AC,∴∠ABC=∠ACB,∴∠MBC=∠MCB,∴MB=MC,在△AMB和△AMC中,∴△AMB≌△AMC,∴∠BAM=∠CAM,即AM平分∠BAC;(2)如图②AB=AC,BD=CE,AM不平分∠BAC,以C为圆心,CE为半径作弧,交AB于H,作CF⊥AB于F,BG⊥AC于G,则CH=CE=BD,∴∠CHE=∠CEH,由②得,△HCF≌△DBG,∴∠BDC=∠CHB,∵∠BEC+∠CEH=180°,∴∠BEC+∠BDC=180°.24.解:(1)证明:∵折叠,使点A落在EF上的点G处,折痕为BH,∴AB=BG,∵将长方形ABCD沿EF折叠,较长的两边BC,AD重合,折痕为EF,∴EF⊥AB,AE=BE,∴AG=BG,∴AB=BG=AG,∴△ABG是等边三角形;(2)如图③,过点G作GM⊥BC于M,∴四边形BEGM是长方形,∴EG=BM,由(1)知,EG是等边三角形ABG的高,∵AB=8,∴BG=8,BE=4,根据勾股定理得,EG==4,∴BM=4<8,∴当a<8时,折不出边长为8的等边三角形的说法是错误的,即:a≥4时能折出一个边长为8的等边三角形;(3)如图②,①将图①纸片对折,使较长的两边BC,AD重合,折痕为EF,再打开纸片,②再折叠,使点A落在EF上的点G处,折痕为BH,③将△BGH沿着BG折叠,得到△BGM,则△BHM是等边三角形.参考答案一、选择题(共10小题,每小题3分,满分30分)1.C.2.D.3.C.4.A.5.D.6.A.7.B.8.C.9.A.10.C.二、填空题(每小题3分,共24分)11.x≤4.12.(0,0).13.20.14.2.15.OA=OC.16.2.(答案不唯一,k>0即可)17.根据SAS证明△AOB≌△COD 18.7.三.解答题(46分)19.解:(1)如图,△A1B1C1为所作;(2)如图,△A2B2C2为所作.20.证明:在△ABD和△ABC中,∴△ABC≌△ABD(AAS).21.解:(1)设y=kx+b,,得,即y与x的函数关系式是y=2.4x﹣21;(2)现有一把高42.0cm的椅子和一张高78.2cm的课桌,它们不配套,理由:当x=42.0时,y=2.4×42.0﹣21=79.8,∵78.2≠79.8,∴现有一把高42.0cm的椅子和一张高78.2cm的课桌,它们不配套.22.解:(1)三角形的第三边x满足:7﹣3<x<3+7,即4<x<10.因为第三边又为奇数,因而第三边可以为5、7或9.故要制作满足上述条件的三角形木框共有3种.(2)制作这种木框的木条的长为:3+5+7+3+7+7+3+7+9=51(分米),∴51×8=408(元).答:至少需要408元购买材料.23.解:∵∠ADB=120°,∴∠BDC=60°,∵∠A=30°,∴∠ABD=30°=∠A,∴AD=BD.在Rt△BCD中,∠BCD=90°,∠BDC=60°,BD=60m,∴∠CBD=30°,CD=BD=30m.24.证明:∵AC∥BD,∴∠A=∠B,在△ACO和△BDO中∴△ACO≌△BDO∴OA=OB,∵AE=BF,∴OE=OF,在△COE和△DOF中∴△COE≌△DOF,∴∠OEC=∠OFD,∴CE∥DF.人教版2020--2021学年度第一学期八年级数学期末检测题及答案题号一二三总分得分时间:120分钟满分:120分一、选择题(每小题3分,共30分)1.(3分)下列计算错误的是()A. =B. =a﹣bC. =D.﹣=﹣2.(3分)若x2﹣kxy+9y2是一个整式完全平方后的结果,则k值为()A.3 B.6 C.±6 D.±813.(3分)若等腰三角形的周长为16cm,其中一边长为4cm,则该等腰三角形的底边为()A.4cm B.6cm C.4cm或8cm D.8cm4.(3分)已知A,B两点的坐标分别是(﹣2,3)和(2,3),则下面四个结论:①A,B关于x轴对称;②A,B关于y轴对称;③A,B关于原点对称;④A,B之间的距离为4,其中正确的有()A.1个B.2个C.3个D.4个5.(3分)一个多边形的每一个外角都等于36°,则该多边形的内角和等于() A.1080°B.900°C.1440°D.720°6.(3分)如图所示,△ABC是等边三角形,且BD=CE,∠1=15°,则∠2的度数为()A.15°B.30°C.45°D.60°7.(3分)如图,点A,B分别是∠NOP,∠MOP平分线上的点,AB⊥OP于点E,BC⊥MN于点C, AD⊥MN于点D,则以下结论错误的是()A.AD+BC=AB B.∠AOB=90°C.与∠CBO互余的角有2个D.点O是CD的中点8.(3分)关于x的分式方程=2的解为正数,则m的取值范围是()A.m>﹣1 B.m≠1 C.m>1且m≠﹣1 D.m>﹣1且m≠1 9.(3分)如图,将△ABC沿直线DE折叠后,使得点B与点A重合.已知AC=4cm,△ADC的周长为15cm,则BC的长()A.8cm B.11cm C.13cm D.19cm10.(3分)有两块面积相同的试验田,分别收获蔬菜900kg和1500kg,已知第一块试验田每亩收获蔬菜比第二块少300kg,求第一块试验田每亩收获蔬菜多少千克.设第一块试验田每亩收获蔬菜xkg,根据题意,可得方程()A.B.C.D.二、填空题(共6小题,每小题3分,满分18分)11.(3分)计算:6a2b÷2a= .12.(3分)若a+b=5,ab=3,则2a2+2b2= .13.(3分)若分式的值为零,则x的值是.14.(3分)如图,已知AB∥CF,E为DF的中点,若AB=11cm,CF=5cm,则BD= cm.15.(3分)如图,已知∠ACB=90°,BD=BC,AE=AC,则∠DCE= 度.16.(3分)如图,AB∥CD,点P为CD上一点,∠EBA、∠EPC的角平分线于点F,已知∠F=40°,则∠E= 度.三、解答题(共8小题,共72分)17.(8分)计算:(1)1﹣;(2).18.(8分)把下列各式因式分解:(1)9a2(x﹣y)+4b2(y﹣x)(2)(x2y2+1)2﹣4x2y219.(8分)解方程:(1)+1=;(2)20.(8分)如图,在折纸活动中,小明制作了一张△ABC的纸片,点D,E分别在边AB,AC上,将△ABC沿着DE折叠压平,A与A′重合,若∠A=75°,求∠1+∠2的度数.21.(9分)如图,∠BAD=∠CAE=90°,AB=AD,AE=AC.(1)证明:BC=DE;(2)若AC=12,CE经过点D,求四边形ABCD的面积.22.(9分)如图,在长度为1个单位长度的小正方形组成的正方形中,点A,B,C在小正方形的顶点上.(1)在图中画出与△ABC关于直线l成轴对称的△A′B′C′(2)三角形ABC的面积为;(3)在直线l上找一点P,使PA+PB的长最短.23.(10分)近年来,安全快捷、平稳舒适的中国高铁,为世界高速铁路商业运营树立了新的标杆.随着中国特色社会主义进入新时代,作为“中国名片”的高速铁路也将踏上自己的新征程,跑出发展新速度,这就意味着今后外出旅行的路程与时间将大大缩短,但也有不少游客根据自己的喜好依然选择乘坐普通列车;已知从A地到某市的高铁行驶路程是400千米,普通列车的行驶路程是高铁行驶路程的1.3倍,请完成以下问题:(1)普通列车的行驶路程为多少千米?(2)若高铁的平均速度(千米/时)是普通列车平均速度(千米/时)的2.5倍,且乘坐高铁所需时间比乘坐普通列车所需时间缩短3小时,求普通列车和高铁的平均速度.24.(12分)如图1,直线AB分别与x轴、y轴交于A、B两点,OC平分∠AOB 交AB于点C,点D为线段AB上一点,过点D作DE∥OC交y轴于点E,已知AO=m,BO=n,且m、n满足n2﹣12n+36+|n﹣2m|=0.(1)求A、B两点的坐标;(2)若点D为AB中点,延长DE交x轴于点F,在ED的延长线上取点G,使DG=DF,连接BG.①BG与y轴的位置关系怎样?说明理由;②求OF的长;(3)如图2,若点F的坐标为(10,10),E是y轴的正半轴上一动点,P是直线AB上一点,且P的横坐标为6,是否存在点E使△EFP为等腰直角三角形?若存在,求出点E的坐标;若不存在,说明理由.参考答案一、选择题1.B.2.C.3.A.4.B.5.C.6.D.7.C.8.D.9.B.10.C.二、填空题11.3ab.12.38.13.﹣2.14.6.15.45.16.80.三、解答题17.解:(1)原式=1﹣•=1﹣=(2)原式=﹣=﹣=﹣=﹣18.解:(1)9a2(x﹣y)+4b2(y﹣x)=(x﹣y)(9a2﹣4b2)=(x﹣y)(3a+2b)(3a﹣2b);(2)(x2y2+1)2﹣4x2y2=(x2y2+1+2xy)(x2y2+1﹣2xy)=(xy﹣1)2(xy+1)2.19.解:(1)+1=,4x+2x+6=7,6x=1,x=,检验:当x=时,2(x+3)≠0.故原方程的解是x=;(2),12﹣2(x+3)=x﹣3,12﹣2x﹣6=x﹣3,﹣2x﹣x=﹣3﹣12+6,﹣3x=﹣9,x=3,检验:当x=3时,(x+3)(x﹣3)=0.故原方程无解.20.解:∵△A′DE是△ABC翻折变换而成,∴∠AED=∠A′ED,∠ADE=∠A′DE,∠A=∠A′=75°,∴∠AED+∠ADE=∠A′ED+∠A′DE=180°﹣75°=105°,∴∠1+∠2=360°﹣2×105°=150°.21.(1)解:∵∠BAD=∠CAE=90°,∴∠BAC+∠CAD=∠EAD+∠CAD,∴∠BAC=∠EAD.在△ABC和△ADE中,∴△ABC≌△ADE(SAS).∴BC=DE(2)∵△ABC≌△ADE,∴S△ABC =S△ADE,∴S四边形ABCD =S△ABC+S△ACD=S△ADE+S△ACD=S△ACE=×122=72.22.解:(1)△A′B′C′如图所示;(2)S△ABC=6×5﹣×6×1﹣×5×5﹣×4×1,=30﹣3﹣12.5﹣2,=30﹣17.5,=12.5;故答案为:12.5;(3)如图,点P即为所求的使PA+PB的长最短的点.23.解:(1)普通列车的行驶路程为:400×1.3=520(千米);(2)设普通列车的平均速度为x千米/时,则高铁的平均速度为2.5千米/时,则题意得:=﹣3,解得:x=120,经检验x=120是原方程的解,则高铁的平均速度是120×2.5=300(千米/时),答:普通列车的平均速度是120千米/时,高铁的平均速度是300千米/时.24.(1)由n2﹣12n+36+|n﹣2m|=0.得:(x﹣6)2+|n﹣2m|=0,∴n=6,m=3,∴A(3,0),B(0,6).(2)①BG⊥y轴.在△BDG与△ADF中,,∴△BDG≌△ADF∴BG=AF,∠G=∠DFA∵OC平分∠ABC,∴∠COA=45°,∵DE∥OC,∴∠DFA=45°,∠G=45°.∵∠FOE=90°,∴∠FEO═45°∵∠BEG=45°,∴∠EBG=90°,即BG与y轴垂直.②从①可知,BG=FA,△BDE为等腰直角三角形.∴BG=BE.设OF=x,则有OE=x,3+x=6﹣x,解得x=1.5,即:OF=1.5.(3)∵A(3,0),B(0,6).∵直线AB的解析式为:y=﹣2x+6,∵P点的横坐标为6,故P(6,﹣6)要使△EFP为等腰直角三角形,必有EF=EP,且∠FEP═90°,如图2,过F、P分别向y轴作垂线垂足分别为M、N.∵∠FEP═90°∴∠FEM+∠PEN=90°,又∠FEM+∠MFE=90°∴∠PEN=∠MFE∴Rt△FME≌Rt△ENP∴ME=NP=6,∴OE=10﹣6=4.即存在点E(0,4),使△EFP为等腰直角三角形。
人教版八年级语文上册期末试卷及答案(2020年)

人教版八年级语文上册期末试卷及答案(2020年)人教版八年级语文上册期末试卷及答案(2020年)满分:120分,考试时间:120分钟一、语言的积累与运用。
(35分)1、下列加点字注音,全部正确的一项是()A.洗漱(shù)一绺(liǔ)无垠(yín)锐不可当(dǎng)B.不辍(chuò)轮廓(kuò)盎然(yàng)深恶痛疾(è)C.踱步(duó)琐屑(xiè)脸颊(jiá)丑陋可憎(zēng)D.轻盈(yíng)悄然(qiǎo)胆怯(qiè)猝不及防(cù)2、下列短文中,加点词的用法正确的一项是()A.在雨后的阳光下,树叶上的露珠闪闪发光,它们好像是天空中的星星掉落到了地上,给人一种神秘而美丽的感觉。
B.在公园里,人们在草地上奔跑,孩子们在玩耍,狗狗在追逐,大家都在享受这美好的时光。
C.在路上,我看到一位老人摔倒了,我赶紧上前去扶他起来,他感激地望着我,说了一声“谢谢”。
D.在音乐会上,演奏家们用心演奏,观众们鼓掌欢呼,整个音乐厅充满了热烈的气氛。
3、下列加点的成语使用不正确的一项是()A.“蛟龙号”的深潜成功、航空母舰的首航,令国人津津乐道。
B.农村补贴、家电下乡等惠农政策对促进消费拉动内需的作用是不言而喻的。
C.欢庆“元旦”的晚会上,XXX模仿的小品让我们都忍俊不禁地开怀大笑。
D.房屋倒塌,道路扭曲,电力和通讯中断,触目惊心的震后景象凸现了地震的威力。
4、下列句子中,没有语病的一项是()A.他的写作水平不但在全校冒尖,而且常常居全班之冠。
B.通过理论研究,全体干部进一步提高了认识水平。
C.有关部门最近发出通知,要求各地在中考阶段严防安全不出问题。
D.有没有团队精神和拼搏精神,是衡量一个优秀球队的标准之一。
5、下列没有使用修辞手法的一项是()A.火中有你万里的躯体/有你千年的面容/有你的云你的树你的风B.蝉翼般轻轻滑落的槐树叶,细看时,还沾着些故国的泥土啊C.老朋友,我的心弦紧绕着你,就像你的树皮一样与你连在一起!D.星光因你而闪烁/XXX因你而摇曳6、请选出下列句子排序正确的一项()①在南坡,带状分布的原始云杉林海连绵不断,棵棵巨杉像一把把利剑,直插云天。
- 1、下载文档前请自行甄别文档内容的完整性,平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益,请联系客服反馈,我们会尽快为您处理(人工客服工作时间:9:00-18:30)。
八年级上册全书测试题一、阅读理解A( )56. Who is the oldest of the four students?A. Li Shan.B. Wang Hui.C. Zhang Min.D. Zhao Fang.( )57. What does Li Shan think the future of schools will be like?A. Multimedia will be used in schools.B. There will be no teacher in the classroom.C. Students will learn on computers at home.D. Students will only take a few disks to school.( )58.Zhang Min thinks students can take classes by or on the Internet in the future A. watching TV B. reading booksC. listening to tapesD. using e-textbooks( )59. All the four think that theis needed for learning in the futureA. TVB. diskC. movieD. computer( )60. Which of the following is NOT true according to the table?A. Learning will become easier and more interesting.B. Students don' t need to buy many new dictionaries.C. A teacher will still be necessary for each classroom.D. You can connect your computer with the school network for free.BDADCBIn the forest, everything was great and everyone was happy before Jemima came there.Jemima was a very tall giraffe(长颈鹿)with along neck(脖子). She was the noisiest and the most gossipy(说闲话、八卦)animal in the forest.She liked to watch everything and told everyone what happened. That made so many animals unhappy. They had a meeting and decided to teach her a lesson.At that time Big Bongo the monkey decided to move to a new house. Jemima was so curious about the new house. One night she walked quietly to Big Bongos bedroom window. The window was open and she put her head inside. She was just on time to see Big Bongo leaving the bedroom. Jemima put her head further so that she could follow him into the next room. It was dark in the house and she couldn't see very well, but she followed Big Bongo into another room, and then another...At last Jemima couldn't follow Big Bongo any more. Her neck wasn't long enough Big Bongo ran around his house, and Jemimas neck was in a tangle(统成一团), Then all the other animals came to the house and told Jemima what they thought of her. Jemimas face turned red. She decided that she would not use her neck to poke(探听、干涉)into the lives of others.( )41. Many animals in the forest were unhappy with Jemima becauseA. she had a long neckB. she was new to the forestC. she was noisy and gossipyD. she liked to do everything( )42. What does the underlined word "curious" mean in Chinese?A.满意的B.疯狂的C.自信的D.好奇的( )43. Big Bongo ran around his new house toA. look at it quicklyB. teach Jemima a lessonC. show his friends aroundD. put his things in their places( )44. The other animals in the forest wanted to tell Jemima thatA. they didn't want her to live in the forestB. she couldn't poke into the lives of othersC. she couldn't go into others houses at nightD. they didn't like to make friends with tall animals( )45. Which of the following is TRUE according to this passage?A. Jemima used her neck to follow Big Bongo into his houseB. Big Bongo asked Jemima to come to his new house.C. Jemimas neck was long enough to see every room in the house.D. Bid Bongos new house was tall enough for Jemima to stand in.CDBBAHobbies are very important to a person. Without having any hobby, life won' t be as colorful as it should be.I have lots of hobbies , such as collecting stamps, playing musical instruments (乐器) , reading, and doing sport activities. When I am free, I will spend time on my hobbies. When I am in a blue mood(情绪低落) ,I will also do my hobbies to cheer myself up. Hobbies can help us improve our moods. Many hobbies need you to put your heart in them.For example, when you play a musical instrument, you have to practice over and over to perform (表演) good music. After a period(一段时期)if you still enjoy it , gradually(逐渐地)it will become a hobby of yours. But remember , a hobby is like gold (金子)under the ground;no hobby will come to your unless (除非) you dig it out. If you can see study as one of your hobbies, learning will be more enjoyable. I hope all of you can find your own hobbies and also have fun from them.( )51.What makes our life colorful?A.Playing musical instruments.B.Collecting stamps.C.The blue mood.D.The hobbies.( )52.Hobbies sometimes can make a personA.in a blue moodB.find gold under the groundC.cheer himself/herself upD.perform good( )53. If we want to have a hobby,we mustA.practice over and over.B.put our heart in itC.spend a lot of time on it.D.all the above.( )54.How can we make our study enjoyableA.Practice over and overB.Improve our moods.C.See our study as a hobby.D.We shouldn' t have hobbies( )55. Which of these is not true?A. Hobbies are important for a person.B. Playing musical instruments is a kind of hobby.C. If we often do something and don't enjoy doing it, it will be our hobbies someday.D. A hobby can be gold if we dig it.DCBCCWater is important. We all need water. Most people drink about two liters (升) every day.61 .In some countries, there is a lot of clean water. But in other places, clean water is hard to find. This is a big problem. Today, about 20% of people don' t always have enough water. 62 .63 .There isn' t a lot of rain. Sometimes people build cities in those places. I don' t think it is a good idea. Other places do have enough water. 64 .They waste too much of it.So we should help save water. We can save water at home. We can take shorter showers. 65 .We can also clean our cars less often.Can you think of other ways to save water?A. But people in these places don' t know how to use water well.B. By 2025, about 70% of people around the world might not have enough water.C. We can turn off the tap (关掉水龙头) when we do the dishes or brush our teeth.D. Water helps us grow food, cook and stay clean.E. Some places are always very dry.DBEAC二、完型填空New Year' s Day is coming. I think 36 of you are going to make New Year' s resolutions. What kind of resolutions should you make? Let me 37 you some advice.First, your New Year' s resolutions should be 38 for you. Be sure that they are good for your study 39 make you healthier. For example, going to bed late at night is not a good resolution. It is bad for your 40Second, your New Year' s resolutions should not be 41 for you to carry out (实施). Don' t 42 them sound impossible. For example, flying to the moon is difficult for almost 43 .You' d better make small and simple ones, so you can make them come true next st, don' t forget to make a 44 . It will help you a lot. It' s a good idea to write down 45 you need to do every day, and then just do it.( )36. A. much B. many C. few D. little( )37. A. give B. take C. follow D. write( )38. A. necessary B. important C. suitable D. special( )39. A. so B. but C. as D. or( )40. A. time B. work C. health D. dream( )41. A. easy B. hard C. useful D. possible( )42. A. make B. bring C. think D. wonder( )43. A. none B. nobody C. somebody D.anybody( )44. A. plan B. choice C. message D. question( )45. A. how B. when C. what D. whyBACDC BADAC三、语篇填空第一节two wonderful after what readhe so think afraid storyOnce there was a king. He liked to write stories. He 71 his stories were good so he liked to show them to people. As people were 72 of him, they all said his stories were very great.One day, the king showed some of his 73 stories to a famous writer. He wanted the writer to praise(赞美) these 74 .But the writer always tells the truth.He said they were 75 bad that he should throw them into the fire. The king got very angry and sent 76 to prison(监狱).Many people didn't dare(敢于)to talk about it. 77 some time, the king made him free and asked him to come to his palace(宫殿).For a 78 time, the king showed some of his new stories. The king asked the writer 79 he thought of them.Guess! What happened next? After 80 them, the writer at once turned to the soldiers and said. "Take me back to the prison."71 72 73 74 7576 77 78 79 80thought afraid wonderful stories sohim After second what reading第二节Dear Alice,I just got back from my summer vacation. I went to Bejing. The weather 66 perfect, not too hot and I saw so many interesting things. I walked along the Great Wall.I also visited Tian'anmen Square 67 the Summer Palace. The buildings were beautiful. The food was delicious, but it was really spicy sometimes. And the people were 68 . I don't speak Putonghua, 69 sometimes that was a little difficult.I had a wonderful time. I 70 to come back to next year!66 67 68 69 70is and friendly so want四、补全对话A: Hello!T om,you look so well these days.B: Thanks.I often play basketball after school.A: 81.B: No.I don't want to be a basketball player. You know I was not in good health before.82. A: You are right. To keep healthy is the most important.83B: I want to be a math teacher when I grow up. It's my dream job.A: I see. How are you going to do about that?В: 84.A: Oh,you're great.85.Can you go with me tonight?B: Sure.l like watching movies. When will we meet?A: At half past seven. OK?81.Do you want to be a basketball player?82.1 just play it to keep healthy./l just keep healthy..83.What are you going to be when you grow up?/What do you want to be when you gr owup..84.Im going to study math hard85.There will be a film tonight....。