初三数学试卷 共4页 第 页 1
2016学年第二学期初三数学教学质量检测试卷
(考试时间100分钟,满分150分) 2017.4
考生注意:
1.本试卷含三个大题,共25题.答题时,考生务必按答题要求在答题纸规定的位置上作答,在草稿
纸、本试卷上答题一律无效.
2.除第一、二大题外,其余各题如无特别说明,都必须在答题纸的相应位置上写出证明或计算的主要步骤.
一、单项选择题(本大题共6题,每题4分,满分24分)
1.已知 3=4x y ,那么下列各式中正确的是( ) A.74=+y x y ; B. 3-=y x x ; C.3
102=+x y x ; D. x -y y =14 . 2.把不等式组???<-≥+0
2,132x x 的解集表示在数轴上,正确的表示为( )
3.在正方形网格中,△ABC 的位置如图所示,则cos ∠B 的
值为( )
A .12;
B .22;
C .3;
D .3. 4.如图,在四边形ABCD 中,动点P 从点A 开始沿A →B →C →D
的路径匀速前进到点D 为止.在这个过程中,△APD 的面积S 随时
间t 的变化关系用图像表示正确的是( )
5.已知P 为线段AB 的黄金分割点,且AP <PB ,则( )
A. AP 2=AB ·PB ;
B. AB 2=AP ·PB ;
C. PB 2=AP ·AB ;
D. AP 2+BP 2=AB 2.
t S
t S t S t S D C B A O
O
O O
初三数学试卷 共4页 第 页 2
6.下列说法中,正确的是( )
A. 一组数据-2,-1,0,1,1,2的中位数是0;
B.质检部门要了解一批灯泡的使用寿命,应当采用普查的调查方式;
C. 购买一张福利彩票中奖是一个确定事件;
D. 分别写有三个数字-1,-2,4的三张卡片(卡片的大小形状都相同),从中任意抽取两张,则卡片上的两数之积为正数的概率为13
. 二、填空题(本大题共12题,每题4分,满分48分)
7.计算:3
13a b ??= ???
_________.
8.在实数范围内因式分解:23x -=_________. 9.已知函数x
x x f 1)(+
=,那么)(1-2f =_________. 10.已知反比例函数x k y 1-=的图象经过一、三象限,则实数k 的取值范围是_________. 11.抛物线a x x y ++=2-2的对称轴是_________.
12.11x -=的解为_________.
13.已知关于x 的方程02-2=+k kx x 有两个相等的实数根,那么实数k =_________.
14.某物流仓储公司用A、B两种型号的机器人搬运物品,已知A 型机器人比B 型机器人每小时多搬运20千克物品,A 型机器人搬运1000千克物品所用时间与B 型机器人搬运800千克物品所用时间相等,设A 型机器人每小时搬运物品x 千克,列出关于x 的方程为_________.
15.化简:=-)313-2b a a (________.
16.如图,在菱形ABCD 中,EF ∥BC ,
3
1=BE AE ,EF =3, 则CD 的长为________.
17.在△ABC 中,已知BC =4cm ,以边AC 的中点P 为圆心1cm 为半径画⊙P ,以边AB 的中点Q 为圆心x cm 长为半径画⊙Q ,如果⊙P 与⊙Q 相切,那么x =_________cm .
18.如图,在Rt △ABC 中,AB=AC ,D 、E 是斜边BC 上两点,且
∠DAE =45°.设BE =a ,DC =b ,那么AB =_________.(用含a 、b 的式
子表示AB )
初三数学试卷 共4页 第 页 3
三、解答题:(本大题共7题,满分78分)
19.(本题满分10分)计算:01)2017(45tan 33)2
1(++---ο.
20.(本题满分10分)解方程组:???=+++=0
62-30-4222y x xy x y x ,.
21.(本题满分10分) 已知直线32
1-+=x y 与x 轴、y 轴分别交于A 、B 两点,设O 为坐标原点. (1)求∠ABO 的正切值; (2)如果点A 向左平移12个单位到点C ,直线l 过点C 且与直线1-
32y x =+平行,求直线l 的解析式.
22.(本题满分10分)
小明在海湾森林公园放风筝.如图所示,小明在A 处,风筝飞到C 处,
此时绳长BC 为40米,若小明双手牵住绳子的底端B 距离地面1.5米,
从B 处测得C 处的仰角为60°,求此时风筝离地面的高度CE .
(计算结果精确到0.1)
23.(本题满分12分)
如图,在△ABC 中,点P 是AC 边上的一点,过点P 作与
BC 平行的直线PQ ,交AB 于点Q ,点D 在 BC 边上,联结
AD 交PQ 于点E ,且CP QE CD BD
=,点G 在BC 的延长线上,∠ACG 的平分线CF 交直线PQ 于点F .
(1)求证:PC =PE ;
(2)当P 是边AC 的中点时,求证:四边形AECF 是矩形.
3 1.732≈
24.(本题满分12分)
已知△OAB在直角坐标系中的位置如图,点A在第一象限,点B在x轴正半轴上,OA=OB=6,
∠AOB=30°.
(1)求点A、B的坐标;
(2)开口向上的抛物线经过原点O和点B,设其顶点为E,当△OBE为
等腰直角三角形时,求抛物线的解析式;
2,
(3)设半径为2的⊙P与直线OA交于M、N两点,已知MN=3
P(m,2)(m>0),求m的值.
25.(本题满分14分)
如图,△ABC的边AB是⊙O的直径,点C在⊙O上,已知AC=6 cm,BC=8 cm,点P、Q分别在边AB、BC上,且点P不与点A、B重合,BQ=k·AP(k >0),连接PC、PQ.
(1)求⊙O的半径长;
(2)当k=2时,设AP=x,△CPQ的面积为y,求y关于x的函数关系式,并写出定义域;
(3)如果△CPQ∽△ABC,且∠ACB=∠CPQ,求k的值.
初三数学试卷共4页第页4
初三数学试卷 共4页 第 页 5
2016学年第二学期初三数学教学质量检测试卷
参考答案及评分建议2017.4
一、选择题:
1.A ; 2.B ; 3.B ; 4.C ; 5.C ; 6.D .
二、填空题:
7.3ab ; 8
.(
x x +; 9
. 10.1k >; 11.直线1x =; 12.2x =;
13.0或1; 14.100080020
x x =-; 15.3a b +r r ; 16.12; 17.1或3; 18
.2++ 三、解答题:
19.解:原式
=(231-+. ·························································································· (8分)
. ··············································································································· (2分)
20.解:由①得20x y +=或20x y -=. ········································································· (2分)
原方程组可化为 (Ⅰ)2203260.x y x xy x y +=??-+++=?,或(Ⅱ)2203260.x y x xy x y -=??-+++=?
, ········· (4分) 解(Ⅰ),方程组无解; ························································································ (1分)
解(Ⅱ)得方程组的解是1124x y =-??=-?,;2236x y =-??=-?,.
···················································· (2分) 所以,原方程组的解为1124x y =-??=-?,;22
36x y =-??=-?,. ························································ (1分) 21.解:(1)由题意得,A (6,0),B (0,3). ························································· (3分) 在Rt △ABO 中,6tan 23
OA ABO OB ∠===. ······································································ (2分) (2)∵点A 向左平移12个单位得到点C ,∴C (6-,0). ··························· (1分) ∵直线l 与直线1+32y x =-
平行,
初三数学试卷 共4页 第 页 6
∴设直线l 的解析式为12
y x b =-+. ··················································································· (1分) ∵直线l 经过点C ,∴()1062
b =-?-+,∴b=3-. ·································· (2分) ∴直线l 的解析式为132
y x =--. ································································ (1分) 22.解:过点B 作BD //AE ,交CE 于点D .
由题意,得BD ⊥CE ,AB =ED=1.5,∠CBD =60°,BC =40. ································· (2分) 在Rt △BCD 中, ∵sin CD CBD BC
∠=,∴sin604034.64CD =??≈. ······································ (6分) ∵CE =ED +DC ,∴CE =1.5+34.64=36.1. ·································································· (1分) 答:此时风筝离地面的高度约为36.1米. ··························································· (1分)
23.证明:(1)∵PQ //BC , ∴QE AE BD AD =,AE EP AD DC
= ······································································· (2分) ∴
QE EP BD DC
= ∵CP QE CD BD =, ∴CP EP CD DC =. ··························································································· (1分) ∴PC =PE . ····································································································· (1分)
(2)∵CF 平分∠ACG ,∴∠PCF =∠FCG , ···························································· (1分)
∵PQ //BC ,∴∠PFC =∠FCG , ······································································· (1分)
∴∠PFC =∠PCF , ···························································································· (1分)
∴PC =PF .········································································································ (1分)
∵PC =PE
∴PE=PF
∵P 是AC 的中点
∴AP =CP ··········································································································· (1分)
∴四边形AECF 是平行四边形. ······································································· (1分)
∴AC =2PC ,EF =2PE
初三数学试卷 共4页 第 页 7
∵PC =PE
∴AC=EF ··········································································································· (1分)
∴四边形AECF 是矩形 . ·············································································· (1分)
24.解:(1)∵OB =6,∴ B (6,0). ············································································· (1分)
过点A 作AH ⊥x 轴,垂足为点H .
∵OA =6,∠AOB =30°,∴AH =3,OH
= ·············································· (1分)
∴ A
(3). ·························································································· (1分)
(2)∵抛物线经过原点O 和点B ,∴该抛物线的对称轴为直线3x =. ·········· (1分)
设该抛物线与x 轴交于点D ,
∵△OBE 为等腰直角三角形,
∴ED =OD=BD .∴ E (3,3-). ··································································· (1分)
设该抛物线的解析式为()233y a x =--.
将原点(0,0)代入得,13a =
. ································································· (1分) ∴()21333
y x =--. ···················································································· (1分) (3)设直线OA 的解析式为y kx =.
∵A
(3
)∴y x =,当2y =
时,x = ······························ (1分) 设直线2y =与直线OA 交于点Q ,得∠PQA =30°.
当点P 在点Q 右侧时,
过点P 作PG ⊥MN ,垂足为点G
.由垂径定理,得NG = ················· (1分)
∴cos 2PNG ∠=,∴∠PNG =30°. ··························································· (1分)
∴点N 与点Q
重合,∴2m =, ························································· (1分)
当点P 在点Q 左侧时,
同理可得,点M 与点Q
重合,∴2m =. ········································· (1分)
25.解:(1)联结OC .
∵AB 是⊙O 的直径,
∴OA =OB =OC , ································································································· (1分)
∴∠OAC =∠OCA ,∠OCB =∠OBC , ···························································· (1分)