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2012年厦门中考数学试题及答案

2012年厦门中考数学试题及答案
2012年厦门中考数学试题及答案

2012年厦门市初中毕业及高中阶段各类学校招生考试

数 学

(试卷满分:150分 考试时间:120分钟)

准考证号 姓名 座位号

注意事项:

1.全卷三大题,26小题,试卷共4页,另有答题卡. 2.答案一律写在答题卡上,否则不能得分. 3.可直接用2B 铅笔画图.

一、选择题(本大题有7小题,每小题3分,共21分.每小题都有四个选项,其中有且只有

一个选项正确) 1. -2的相反数是

A .2

B .-2

C .±2

D .-1

2

2.下列事件中,是必然事件的是

A . 抛掷1枚硬币,掷得的结果是正面朝上

B . 抛掷1枚硬币,掷得的结果是反面朝上

C . 抛掷1枚硬币,掷得的结果不是正面朝上就是反面朝上

D .抛掷2枚硬币,掷得的结果是1个正面朝上与1个反面朝上

3.图1是一个立体图形的三视图,则这个立体图形是 A .圆锥 B .球

C .圆柱

D .三棱锥

4.某种彩票的中奖机会是1%,下列说法正确的是 A .买1张这种彩票一定不会中奖 B .买1张这种彩票一定会中奖 C .买100张这种彩票一定会中奖

D .当购买彩票的数量很大时,中奖的频率稳定在1%

5.若二次根式x -1有意义,则x 的取值范围是 A .x >1 B .x ≥1 C .x <1 D .x ≤1

6.如图2,在菱形ABCD 中,AC 、BD 是对角线, 若∠BAC =50°,则∠ABC 等于 A .40° B .50° C .80° D .100°

7.已知两个变量x 和y ,它们之间的3组对应值如下表所示.

x -1 0 1

y

-1

1

3

则y 与x 之间的函数关系式可能是

C B 图2

D

A

图1俯视图

左视图

正视图

A .y =x

B .y =2x +1

C .y =x 2+x +1

D .y =3

x

二、填空题(本大题有10小题,每小题4分,共40分) 8.计算: 3a -2a = .

9.已知∠A =40°,则∠A 的余角的度数是 . 10.计算: m 3÷m 2= .

11.在分别写有整数1到10的10张卡片中,随机抽取1张

卡片,则该卡片上的数字恰好是奇数的概率是 . 12.如图3,在等腰梯形ABCD 中,AD ∥BC ,对角线AC

与BD 相交于点O ,若OB =3,则OC = . 13.“x 与y 的和大于1”用不等式表示为 . 14.如图4,点D 是等边△ABC 内一点,如果△ABD 绕点A

逆时针旋转后能与△ACE 重合,那么旋转了 度. 15.五边形的内角和的度数是 .

16.已知a +b =2,ab =-1,则3a +ab +3b = ;

a 2+

b 2= .

17.如图5,已知∠ABC =90°,AB =πr ,BC =πr

2

,半径为r

的⊙O 从点A 出发,沿A →B →C 方向滚动到点C 时停止. 请你根据题意,在图5上画出圆心..O 运动路径的示意图; 圆心O 运动的路程是 . 三、解答题(本大题有9小题,共89分) 18.(本题满分18分)

(1)计算:4÷(-2)+(-1)2×40;

(2)画出函数y =-x +1的图象;

(3)已知:如图6,点B 、F 、C 、E 在一条直线上,

∠A =∠D ,AC =DF ,且AC ∥DF . 求证:△ABC ≌△DEF .

图6

A

B

C

D

F

E

图4

A

B

C

D

E

图3

A

B

D

C

O

图5

A

B

C

O

19.(本题满分7分)解方程组: ???3x +y =4,

2x -y =1.

20.(本题满分7分)已知:如图7,在△ABC 中,∠C =90°,点D 、E 分别在边AB 、AC

上,DE ∥BC ,DE =3, BC =9. (1)求 AD

AB

的值;

(2)若BD =10,求sin ∠A 的值.

21.(本题满分7分)已知A 组数据如下:

0,1,-2,-1,0,-1,3.

(1)求A 组数据的平均数;

(2)从A 组数据中选取5个数据,记这5个数据为B 组数据. 要求B 组数据满足两

个条件:①它的平均数与A 组数据的平均数相等;②它的方差比A 组数据的方差大.你选取的B 组数据是 ,请说明理由. 【注:A 组数据的方差的计算式是

S A 2=1

7[(x 1-—x )2+(x 2-—x )2+(x 3-—x )2+(x 4-—x )2+(x 5-—x )2+(x 6-—x )2+(x 7-—x )2]】

图7

A B

C

D

E

22.(本题满分9分)工厂加工某种零件,经测试,单独加工完成这种零件,甲车床需用

x 小时,乙车床需用 (x 2-1)小时,丙车床需用(2x -2)小时.

(1)单独加工完成这种零件,若甲车床所用的时间是丙车床的 2

3

,求乙车床单独加工

完成这种零件所需的时间;

(2)加工这种零件,乙车床的工作效率与丙车床的工作效率能否相同?请说明理由.

23.(本题满分9分)已知:如图8,⊙O 是△ABC 的外接圆,AB 为⊙O 的直径,弦CD

交AB 于E ,∠BCD =∠BAC . (1)求证:AC =AD ;

(2)过点C 作直线CF ,交AB 的延长线于点F ,

若∠BCF =30°,则结论“CF 一定是⊙O 的切线” 是否正确?若正确,请证明;若不正确,请举反例.

图8

F

B

C

E D

O

A

24.(本题满分10分)如图9,在平面直角坐标系中,已知点A (2,3)、B (6,3),连结AB .

如果点P 在直线y =x -1上,且点P 到直线AB 的距离小于1,那么称点P 是线段AB 的“邻近点”.

(1)判断点C( 72,5

2

) 是否是线段AB 的“邻近点”,并说明理由;

(2)若点Q (m ,n )是线段AB 的“邻近点”,求m 的取值范围.

25.(本题满分10分)已知□ABCD ,对角线AC 与BD 相交于点O ,点P 在边AD 上,过

点P 分别作PE ⊥AC 、PF ⊥BD ,垂足分别为E 、F ,PE =PF . (1)如图10,若PE =3,EO =1,求∠EPF 的度数; (2)若点P 是AD 的中点,点F 是DO 的中点,

BF =BC +32-4,求BC 的长.

E F

图10

A

B

C

D

O

P x

y

B

42

6

42O

图9

A

26.(本题满分12分)已知点A(1,c)和点B(3,d )是直线y=k1x+b与双曲线y=k2

x(k2>0)的交点.

(1)过点A作AM⊥x轴,垂足为M,连结BM.若AM=BM,求点B的坐标;

(2)设点P在线段AB上,过点P作PE⊥x轴,垂足为E,并交双曲线y=k2

x(k2>0)

于点N.当PN

NE取最大值时,若PN=

1

2,求此时双曲线的解析式.

2012年厦门市初中毕业及高中阶段各类学校招生考试

数学参考答案及评分标准

说明:

1.解答只列出试题的一种或几种解法.如果考生的解法与所列解法不同,可参照解答中评分标准相应评分;

2.评阅试卷,要坚持每题评阅到底,不能因考生解答中出现错误而中断对本题的评阅.如果考生的解答在某一步出现错误,影响后续部分而未改变本题的内容和难度,视影响的程度决定后继部分的给分,但原则上不超过后续部分应得分数的一半; 3.解答题评分时,给分或扣分均以1分为基本单位.

一、选择题(本大题共7小题,每小题3分,共21分)

题号 1 2 3 4 5 6 7 选项

A

C

A

D

B

C

B

二、填空题(本大题共10小题,每题4分,共40分)

8. a . 9. 50°. 10. m . 11. 1

2. 12.

3. 13. x +y >1.

14. 60.

15. 540°. 16. 5; 6. 17. ;2πr .

三、解答题(本大题共9小题,共89分) 18.(本题满分18分)

(1)解:4÷(-2) +(-1)2×40

=-2+1×1 ····················································································· 4分 =-2+1 ··························································································· 5分 =-1. ···························································································· 6分

(2)解:正确画出坐标系 ··············································································· 8分

正确写出两点坐标 ········································································· 10分 画出直线 ························································································· 12分

(3)证明:∵ AC ∥DF , ……13分

∴ ∠ACB =∠DFE . ……15分 又∵ ∠A =∠D , ……16分 AC =DF , ……17分 ∴ △ABC ≌△EDF . ……18分

19.(本题满分7分)

解1:???3x +y =4, ①2x -y =1. ②

①+②,得 ························································································ 1分 5x =5, ····························································································· 2分 x =1. ······························································································· 4分

A

B

C

D

F

E

将x =1代入 ①,得 3+y =4, ························································································· 5分 y =1. ······························································································· 6分

∴???x =1,y =1.

························································································· 7分 解2:由①得 y =4-3x . ③ ·················································· 1分 将③代入②,得 2x -(4-3x ) =1. ··········································································· 2分 得x =1. ·························································································· 4分 将x =1代入③ ,得 y =4-3×1 ······················································································· 5分 =1. ······························································································ 6分

∴???x =1,y =1.

························································································· 7分 20.(本题满分7分)

(1)解:∵ DE ∥BC ,∴ △ADE ∽△ABC . ……1分

∴ AD AB =DE

BC

. ……2分

∴ AD AB =1

3

.

……3分

(2)解1:∵

AD AB =1

3

,BD =10, ∴

AD AD +10=1

3

················································································ 4分

∴ AD =5 ······················································································· 5分 经检验,符合题意. ∴ AB =15. 在Rt △ABC 中, ·············································································· 6分 sin ∠A =BC AB =35

. ············································································· 7分

解2: ∵

AD AB =1

3

,BD =10, ∴

AD AD +10=1

3

················································································ 4分

∴ AD =5 ······················································································· 5分 经检验,符合题意. ∵ DE ∥BC ,∠C =90° ∴ ∠AED =90° 在Rt △AED 中, ·············································································· 6分 sin ∠A =ED AD =35

. ············································································· 7分

解3:过点D 作DG ⊥BC ,垂足为G . ∴ DG ∥AC .

∴∠A =∠BDG . ············································································· 4分

A B

C

D

E

G

又∵ DE ∥BC ,∴四边形ECGD 是平行四边形. ∴ DE =CG . ···················································································· 5分 ∴ BG =6.

在Rt △DGB 中, ············································································· 6分 ∴ sin ∠BDG =BD GB =35. ·································································· 7分

∴ sin ∠A =3

5

.

21.(本题满分7分)

(1)解:A 组数据的平均数是0+1-2-1+0-1+3

7 ·································· 1分

=0. ······························································ 3分

(2)解1:选取的B 组数据:0,-2,0,-1,3. ···································· 4分

∵ B 组数据的平均数是0. ··························································· 5分 ∴ B 组数据的平均数与A 组数据的平均数相同.

∴ S B 2=

145 ,S A 2=16

7

. ································································ 6分 ∴ 145 >16

7

. ····················································································· 7分

∴ B 组数据:0,-2,0,-1,3.

解2:B 组数据:1,-2,-1,-1,3. ············································ 4分

∵ B 组数据的平均数是0. ··························································· 5分 ∴ B 组数据的平均数与A 组数据的平均数相同.

∵S A 2=167, S B 2=16

5

. ································································ 6分 ∴

165>167

························································································· 7分 ∴ B 组数据:1,-2,-1,-1,3.

22.(本题满分9分) (1)解:由题意得,

x =2

3(2x -2) ····················································································· 1分 ∴ x =4. ························································································· 2分 ∴ x 2-1=16-1=15(小时). ························································· 3分 答:乙车床单独加工完成这种零件所需的时间是15小时. ········· 4分

(2)解1:不相同. ························································································ 5分

若乙车床的工作效率与丙车床的工作效率相同,由题意得, ······· 6分

1x 2-1=1

2x -2 . ·············································································· 7分 ∴ 1x +1=12

.

∴ x =1. ······················································································· 8分 经检验,x =1不是原方程的解. ∴ 原方程无解. ······················· 9分 答:乙车床的工作效率与丙车床的工作效率不相同.

解2:不相同. ························································································ 5分

若乙车床的工作效率与丙车床的工作效率相同,由题意得, ······· 6分 x 2-1=2x -2. ················································································ 7分 解得,x =1. ··················································································· 8分 此时乙车床的工作时间为0小时,不合题意. ······························ 9分 答:乙车床的工作效率与丙车床的工作效率不相同.

23.(本题满分9分)

(1)证明1:∵∠BCD =∠BAC ,

∴ ︵BC =︵

BD .

……1分

∵ AB 为⊙O 的直径, ∴ AB ⊥CD , ……2分 CE =DE . ……3分 ∴ AC =AD . ……4分

证明2:∵∠BCD =∠BAC ,

∴ ︵BC =︵

BD . ············································································· 1分 ∵ AB 为⊙O 的直径, ∴ ︵BCA =︵

BDA . ·································· 2分 ∴ ︵CA =︵DA . ················································································· 3分

∴ AC =AD . ················································································· 4分

证明3:∵ AB 为⊙O 的直径,∴ ∠BCA =90°. ····························· 1分

∴ ∠BCD +∠DCA =90°, ∠BAC +∠CBA =90° ∵∠BCD =∠BAC ,∴∠DCA =∠CBA ········································ 2分

∴ ︵CA =︵DA . ················································································· 3分

∴ AC =AD . ················································································· 4分

(2)解1:不正确. ························································································ 5分

连结OC .

当 ∠CAB =20°时, ······································································ 6分 ∵ OC =OA ,有 ∠OCA =20°.

∵ ∠ACB =90°, ∴ ∠OCB =70°. ·································· 7分 又∵∠BCF =30°, ∴∠FCO =100°, ········································································· 8分 ∴ CO 与FC 不垂直. ···································································· 9分 ∴ 此时CF 不是⊙O 的切线.

解2:不正确. ························································································ 5分

连结OC .

当 ∠CAB =20°时, ······································································ 6分 ∵ OC =OA ,有 ∠OCA =20°.

∵ ∠ACB =90°, ∴ ∠OCB =70°. ·································· 7分 又∵∠BCF =30°, ∴∠FCO =100°, ········································································· 8分

G

A

O

D

E C

B

F

在线段FC 的延长线上取一点G ,如图所示,使得∠COG =20°. 在△OCG 中, ∵∠GCO =80°, ∴∠CGO =80°. ∴ OG =OC . 即OG 是⊙O 的半径.

∴ 点G 在⊙O 上. 即直线CF 与圆有两个交点. ························ 9分 ∴ 此时CF 不是⊙O 的切线.

解3:不正确. ························································································ 5分

连结OC .

当 ∠CBA =70°时, ······································································ 6分 ∴ ∠OCB =70°. ········································································· 7分 又∵∠BCF =30°, ∴∠FCO =100°, ········································································· 8分 ∴ CO 与FC 不垂直. ···································································· 9分 ∴ 此时CF 不是⊙O 的切线. 24.(本题满分10分)

(1)解:点C(72,5

2

) 是线段AB 的“邻近点”. ·········································· 1分

∵72-1=52, ∴点C(72,5

2)在直线y =x -1上. ·························· 2分 ∵点A 的纵坐标与点B 的纵坐标相同, ∴ AB ∥x 轴. ················································································· 3分 ∴C(72,52) 到线段AB 的距离是3-52

∵3-52=1

2<1, ··············································································· 4分

∴C(72,5

2

)是线段AB 的“邻近点”.

(2)解1:∵点Q (m ,n )是线段AB 的“邻近点”,

∴ 点Q (m ,n )在直线y =x -1上, ∴ n =m -1. ·················································································· 5分 ① 当m ≥4时, ·············································································· 6分 有n =m -1≥3. 又AB ∥x 轴,

∴ 此时点Q (m ,n )到线段AB 的距离是n -3. ···························· 7分 ∴0≤n -3<1. ∴ 4≤m <5. ················································································ 8分 ② 当m ≤4时, ·············································································· 9分 有n =m -1≤3. 又AB ∥x 轴,

∴ 此时点Q (m ,n )到线段AB 的距离是3-n . ∴0≤3-n <1. ∴ 3<m ≤4. ·············································································· 10分 综上所述, 3<m <5. 解2:∵点Q (m ,n )是线段AB 的“邻近点”,

∴ 点Q (m ,n )在直线y =x -1上,

∴ n =m -1. ·················································································· 5分 又AB ∥x 轴,

∴ Q (m ,n )到直线AB 的距离是n -3或3-n , ··························· 6分 ① 当0≤n -3<1时, ···································································· 7分 即 当0≤m -1-3<1时, 得 4≤m <5. ·················································································· 8分 ② 当0≤3-n <1时, ···································································· 9分 有0≤3-(m -1)<1时, 得 3<m ≤4. ·············································································· 10分 综上所述,3<m <5.

25.(本题满分10分) (1)解1:连结PO ,

∵ PE =PF ,PO =PO , PE ⊥AC 、PF ⊥BD , ∴ Rt △PEO ≌Rt △PFO . ∴ ∠EPO =∠FPO . ……1分 在Rt △PEO 中,

……2分 tan ∠EPO =EO PE =3

3

……3分

∴ ∠EPO =30°. ∴ ∠EPF =60°. ·········································································· 4分

解2:连结PO , 在Rt △PEO 中, ·············································································· 1分

PO =3+1 =2.

∴ sin ∠EPO =EO PO =1

2. ··································································· 2分

∴ ∠EPO =30°. ·········································································· 3分 在Rt △PFO 中,cos ∠FPO =

PF PO =3

2

,∴∠FPO =30°. ∴ ∠EPF =60°. ·········································································· 4分

解3:连结PO ,

∵ PE =PF ,PE ⊥AC 、PF ⊥BD ,垂足分别为E 、F , ∴ OP 是∠EOF 的平分线. ∴ ∠EOP =∠FOP . ······································································ 1分 在Rt △PEO 中, ·············································································· 2分

tan ∠EOP =PE

EO = 3 ········································································· 3分

∴ ∠EOP =60°,∴ ∠EOF =120°. 又∵∠PEO =∠PFO =90°, ∴ ∠EPF =60°. ·········································································· 4分

(2)解1:∵点P 是AD 的中点,∴ AP =DP . 又∵ PE =PF ,∴ Rt △PEA ≌Rt △PFD . ∴ ∠OAD =∠ODA . ∴ OA =OD . ·················································································· 5分

F P C

B

O

E

D

A

∴ AC =2OA =2OD =BD . ∴□ABCD 是矩形. ········································································ 6分 ∵ 点P 是AD 的中点,点F 是DO 的中点, ∴ AO ∥PF . ··················································································· 7分 ∵ PF ⊥BD ,∴ AC ⊥BD . ∴□ABCD 是菱形. ········································································ 8分 ∴□ABCD 是正方形. ···································································· 9分 ∴ BD =2BC .

∵ BF =34BD ,∴BC +32-4=324

BC .

解得,BC =4. ·············································································· 10分

解2:∵ 点P 是AD 的中点,点F 是DO 的中点,

∴ AO ∥PF . ··················································································· 5分 ∵ PF ⊥BD ,∴ AC ⊥BD . ∴□ABCD 是菱形. ········································································ 6分 ∵ PE ⊥AC ,∴ PE ∥OD .

∴ △AEP ∽△AOD .

∴ EP OD =AP AD =12

. ∴ DO =2PE . ∵ PF 是△DAO 的中位线, ∴ AO =2PF .

∵ PF =PE ,

∴ AO =OD . ··················································································· 7分 ∴ AC =2OA =2OD =BD . ∴ □ABCD 是矩形. ······································································ 8分 ∴ □ABCD 是正方形. ·································································· 9分 ∴ BD =2BC .

∵ BF =34BD ,∴BC +32-4=324

BC .

解得,BC =4. ·············································································· 10分

解3:∵点P 是AD 的中点,∴ AP =DP .

又∵ PE =PF , ∴ Rt △PEA ≌Rt △PFD . ∴ ∠OAD =∠ODA . ∴ OA =OD . ·················································································· 5分 ∴ AC =2OA =2OD =BD . ∴□ABCD 是矩形. ········································································ 6分 ∵点P 是AD 的中点,点O 是BD 的中点,连结PO . ∴PO 是△ABD 的中位线, ∴ AB =2PO . ················································································· 7分 ∵ PF ⊥OD ,点F 是OD 的中点, ∴ PO =PD . ∴ AD =2PO . ∴ AB =AD . ··················································································· 8分

E F

A B C D

O P

∴□ABCD 是正方形. ···································································· 9分 ∴ BD =2BC .

∵ BF =34BD ,∴BC +32-4=324

BC .

解得,BC =4. ·············································································· 10分

解4:∵点P 是AD 的中点,∴ AP =DP .

又∵ PE =PF , ∴ Rt △PEA ≌Rt △PFD . ∴ ∠OAD =∠ODA . ∴ OA =OD . ·················································································· 5分 ∴ AC =2OA =2OD =BD . ∴□ABCD 是矩形. ········································································ 6分 ∵PF ⊥OD ,点F 是OD 的中点,连结PO . ∴PF 是线段OD 的中垂线, 又∵点P 是AD 的中点,

∴PO =PD =1

2BD ············································································· 7分

∴△AOD 是直角三角形, ∠AOD =90°. ··································· 8分 ∴□ABCD 是正方形. ···································································· 9分 ∴ BD =2BC .

∵ BF =34BD ,∴BC +32-4=324

BC .

解得,BC =4. ·············································································· 10分

26.(本题满分12分)

(1)解:∵点A (1,c )和点B (3,d )在双曲线y =k 2

x

(k 2>0)上,

∴ c =k 2=3d ·················································································· 1分 ∵ k 2>0, ∴ c >0,d >0.

A (1,c )和点

B (3,d )都在第一象限. ∴ AM =3d . ··················································································· 2分 过点B 作BT ⊥AM ,垂足为T . ∴ BT =2. ······················································································ 3分 TM =d .

∵ AM =BM , ∴ BM =3d .

在Rt △BTM 中,TM 2+BT 2=BM 2, ∴ d 2+4=9d 2, ∴ d =22

. 点B (3,

2

2

) . ················································································ 4分 (2)解1:∵ 点A (1,c )、B (3,d )是直线y =k 1x +b 与双曲线y =k 2

x

(k 2>0)的交点,

∴ c =k 2,,3d =k 2,c =k 1+b ,d =3k 1+b . ································· 5分 ∴ k 1=-13k 2,b =4

3

k 2.

∵ A (1,c )和点B (3,d )都在第一象限,∴ 点P 在第一象限.

∴ PE NE =k 1x +b k 2

x

=k 1k 2x 2+b k 2

x =-13x 2+43x . ······································································· 6分

∵ 当x =1,3时,PE

NE

=1; 又∵当x =2时,

PE NE 的最大值是43

. ∴ 1≤PE NE ≤4

3. ·············································································· 7分

∴ PE ≥NE . ··················································································· 8分 ∴ PN NE =PE NE -1=-13x 2+4

3x -1. ··················································· 9分 ∴ 当x =2时,

PN NE 的最大值是13. ············································································ 10分 由题意,此时PN =12

∴ NE =3

2. ······················································································ 11分

∴ 点N (2,3

2

) . ∴ k 2=3.

∴ y =3x

. ························································································· 12分

解2:∵ A (1,c )和点B (3,d )都在第一象限,∴ 点P 在第一象限.

∵ PE NE =k 1x +b k 2x =k 1k 2x 2+b k 2

x , 当点P 与点A 、B 重合时,PE

NE =1,

即当x =1或3时,

PE

NE

=1. ∴ 有 k 1k 2+b k 2=-1, 9k 1k 2+3b k 2=-1. ········································ 5分

解得,k 1=-13k 2,b =43

k 2.

∴ PE NE =-13x 2+4

3x . ········································································ 6分 ∵ k 2=-3k 1,k 2>0,∴ k 1<0. ∵ PE -NE =k 1x +b -k 2x =k 1x -4k 1+3k 1x

=k 1( x 2-4x +3x )=k 1 (x -1)(x -3)x , ············································ 7分

又∵当1≤x ≤3时,

(x -1) (x -3) ≤0, ∴ k 1(

(x -1)(x -3)

x

) ≥0.

∴ PE -NE ≥0. ············································································· 8分 ∴

PN NE =PE

NE

-1 =-13x 2+4

3x -1. ································································· 9分

∴ 当x =2时,PN NE 的最大值是1

3. ·················································· 10分

由题意,此时PN =1

2

∴ NE =3

2. ···················································································· 11分

∴ 点N (2,3

2

) . ∴ k 2=3.

∴ y =3x

. ························································································· 12分

解3:∵ 点A (1,c )、B (3,d )是直线y =k 1x +b 与双曲线y =k 2

x

(k 2>0)的交点,

∴ c =k 2,,3d =k 2,c =k 1+b ,d =3k 1+b . ··································· 5分 k 2=3d , k 1=-d ,b =4d .

∴ 直线y =-dx +4d ,双曲线y =3d

x

.

∵ A (1,c )和点B (3,d )都在第一象限,∴ 点P 在第一象限. ∴ PN =PE -NE =-dx +4d -3d

x

=-d ( x 2-4x +3x )=-d (x -1)(x -3)

x , ······································ 6分

又∵当1≤x ≤3时,(x -1) (x -3) ≤0, ∴-d (x -1)(x -3)

x

≥0.

∴ PN =PE -NE ≥0. ····································································· 7分 ∴ PN

NE =-dx +4d -

3d

x 3d

x

································································· 8分

=-13x 2+4

3x -1. ································································· 9分

∴ 当x =2时,PN NE 的最大值是1

3

. ·················································· 10分

由题意,此时PN =1

2

∴ NE =3

2. ······················································································ 11分

∴ 点N (2,3

2) .

∴ k 2=3.

∴ y =3x

. ························································································· 12分

2020年湖南省中考数学模拟试题(含答案)

2020年湖南省中考数学模拟试题含答案 温馨提示: 1.本试卷包括试题卷和答题卡.考生作答时,选择题和非选择题均须作答在答题卡上,在本试题卷上作答无效.考生在答题卡上按答题卡中注意事项的要求答题. 2.考试结束后,将本试题卷和答题卡一并交回. 3.本试卷满分150分,考试时间120分钟.本试卷共三道大题,26个小题.如有缺页,考生须声明. 一、选择题(本大题共10个小题,每小题只有一个正确选项,请将正确选项填涂到答题卡 上.每小题4分,共40分) 1.如果a 与2017互为倒数,那么a 是( ) A . -2017 B . 2017 C . 20171- D . 2017 1 2.下列图形中,是中心对称图形的是( ) A. B. C. D. 3.下列计算正确的是( ) A . 6 33a a a =+ B . 33=-a a C . 5 23)(a a = D . 3 2a a a =?

4.人类的遗传物质是DNA,DNA是一个很长的链,最短的22号染色体与长达30000000个核苷酸,30000000用科学记数法表示为( ) A.3×107 B.30×104 C.0.3×107 D .0.3×10 8 5.如图,过反比例函数)0(>= x x k y 的图像上一点A 作 AB ⊥x 轴于点B ,连接AO ,若S △AOB =2,则k 的值为( ) A .2 B .3 C .4 D .5 6.下列命题:①若a<1,则(a﹣1) a a --=-111 ;②平行四边形既是中心对称图形又是轴对称图形;③9的算术平方根是3;④如果方程ax 2+2x+1=0有两个不相等的实数根,则实数a<1.其中正确的命题个数是( ) A.1个 B.2个 C.3个 D.4个 7.如图,AB ∥ CD,DE⊥ CE,∠ 1=34°,则 ∠ DCE的度数为( ) A.34° B.54° C.66° D.56° (第7题图) (第9题图) 8.一种饮料有两种包装,5大盒、4小盒共装148瓶,2大盒、5小盒共装100瓶,大盒与小盒每盒各装多少瓶?设大盒装x瓶,小盒装y瓶,则可列方程组( ) A. B. C. D . 9.如图,PA 、PB 是⊙O 的切线,切点分别为A 、B .若OA =2,∠P =60°,则?AB 的长为( )

2014厦门中考数学试卷及答案

2014年厦门市初中毕业及高中阶段各类学校招生考试 数 学 (试卷满分:150 考试时间:120分钟) 一、选择题(本大题有7小题,每小题3分,共21分。每小题都有四个选项,其中有且只有一个选项正确) 1、?30sin 的值为 A. 21 B. 22 C. 2 3 D. 1 2、4的算术平方根是 A. 16 B. 2 C. 2- D. 2± 3、2 3x 可以表示为 A. x 9 B. 222x x x ?? C. 2233x x ? D. 222x x x ++ 4、已知直线AB ,CB ,l 在同一平面内,若l AB ⊥,垂足为B ,l CB ⊥,垂足也为B ,则符合题意的图形可以是 5、已知命题A :任何偶数都是8的整数倍。在下列选项中,可以作为“命题A 是假命题” 的反例的是 A. k 2 B. 15 C. 24 D. 42 6、如图1,在△ABC 和△BDE 中,点C 在边BD 上,边AC 交BE 于点F ,若AC=BD ,AB=ED ,BC=BE ,则∠ACB 等于 A.∠EDB B.∠BED C. 21 ∠AFB D. 2∠ABF 7、已知某校女子田径队23人年龄的平均数和中位数都是13岁,但是后来发现其中有一位同学的年龄登记错误,将14岁写成15岁。经重新计算后,正确的平均数为a 岁,中位数为b 岁,则下列结论中正确的是 A.13,13=b a D.13,13=>b a 二、填空题(本大题有10小题,每小题4分,共40分) 8、一个圆形转盘被平均分成红、黄、蓝、白4个扇形区域,向其投掷一枚飞镖,飞镖落在转盘上,则落在黄色区域的概率是__________。 9、代数式1-x 在实数范围内有意义,则x 的取值范围是__________。 10、四边形的内角和是____________。 A C B B l A. l B. B A C l B A C C. l A C B D. A F E B C D 图1

2013年福建厦门中考数学试卷及解析

2013年厦门市初中毕业及高中阶段各类学校招生考试 数 学 (试卷满分:150分 考试时间:120分钟) 准考证号 姓名 座位号 注意事项: 1.全卷三大题,26小题,试卷共4页,另有答题卡. 2.答案一律写在答题卡上,否则不能得分. 3.可直接用2B 铅笔画图. 一、选择题(本大题有7小题,每小题3分,共21分.每小题都有四个选项,其中有且只有一个 选项正确) 1.(2013福建厦门,1,3分).下列计算正确的是( ) A .-1+2=1. B .-1-1=0. C .(-1)2=-1. D .-12=1. 【答案】A (2013福建厦门,2,3分).已知∠A =60°,则∠A 的补角是 A .160°. B .120°. C .60°. D .30°. 【答案】B (2013福建厦门,3,3分).图1是下列一个立体图形的三视图,则这个立体图形是 A .圆锥. B .球. C .圆柱. D .正方体. 俯视图 左视图 主视图图1 【答案】C (2013福建厦门,4,3分).掷一个质地均匀的正方体骰子,当骰子停止后,朝上 一面的点数为5的概率是 A .1. B .15. C .1 6 . D .0.

【答案】C. (2013福建厦门,5,3分).如图2,在⊙O中,︵ AB=︵ AC,∠A=30°,则∠B=A.150°.B.75°. C.60°.D.15°. 图2 【答案】B (2013福建厦门,6,3分).方程 2 x -1 = 3 x的解是 A.3.B.2. C.1.D.0. 【答案】A (2013福建厦门,7,3分).在平面直角坐标系中,将线段OA向左平移2个单位,平移后,点O,A的对应点分别为点O1,A1.若点O(0,0),A(1,4),则点O1,A1的坐标分别是 A.(0,0),(1,4).B.(0,0),(3,4). C.(-2,0),(1,4).D.(-2,0),(-1,4). 【答案】D.

广东省2012中考数学(word版)

2012广东中考数学试题2012-6-22 一选择题(每小题3分,共15分) 1.-5的绝对值是( ) A.5 B.-5 C. 5 1 D.-5 1 2.地球半径约为6 400 000米用科学记数法表示为( ) A.0.64×107 B.6.4×106 C.64×105 D.640×104 3.数据8、8、6、5、6、1、6的众数是( ) A1. B.5 C.6 D.8 4.如图所示几何体的主视图是( ) 5.已知三角形两边的长分别是4和10,则此三角形第三边的长可能是( ) A.5 B.6 C.11 D.16 二、填空题(每小题4分,共20分) 6.分解因式:x x 1022 -= . 7.不等式93-x >0的解集是 . 8.如图,A 、B 、C 是⊙O 上的三个点,∠ABC=25°, 则∠AOC 的度数是 . 9.若x 、y 为实数,且满足033=++ -y x ,则2012 ? ?? ? ??y x 的值是 . 10.如图,在平行四边形ABCD 中,AD=2,AB=4,∠A=30°.以点A 为圆心,AD 的长为半径画弧交AB 于点E ,连结CE ,则阴影部分的面积是 (结果保留π). 三、解答题(每小题解分,共30分) 11.计算:45sin 22-°-()1 281-++. 12.先化简,再求值:()()()233---+x x x x ,其中x =4. E D 30° C B A 4题图 A B C D 8题图 10题图

13.解方程组:()? ??=+=-2.163) 1(4y x y x 14.如图,在△ABC 中,AB=AC ,∠ABC=72°. (1)用直尺和圆规作∠ABC 的平分线BD 交AC 于点D (保留作图痕迹,不要求写作法); (2)在(1)中作出∠ABC 的平分线BD 后,求∠BDC 的度数. 15.已知:如图,在四边形ABCD 中,AB ∥CD ,对角线AC 、BD 相交于点O ,BO=DO. 求证:四边形ABCD 是平行四边形. 四、解答题(每小题名分,共28分) 16.据媒体报道,我国2009年公民出境旅游总人数约为5000万人次,2011年公民出境旅游总 人数约7200万人次.若2010年、2011年公民出境旅游总人数逐年递增,请解答下列问题: (1)求这两年我国公民出境旅游总人数的年平均增长率; (2)如果2012年仍保持相同的年平均增长率,请你预测2012年我国公民出境旅游总人数 约多少万人次? C B A D O C B A 14题图 15题图

2014中考数学模拟试题(新考点必考题型) (58)

中考数学全真模拟试卷 (考试用时:120分钟 满分: 120分) 注意事项: 1.试卷分为试题卷和答题卡两部分,在本试题卷上作答无效.......... 。 2.答题前,请认真阅读答题卡... 上的注意事项。 3.考试结束后,将本试卷和答题卡....... 一并交回。 一、选择题(共12小题,每小题3分,共36分.). 1.2011的倒数是( ). A .12011 B .2011 C .2011- D .12011 - 2.在实数2、0、1-、2-中,最小的实数是( ). A .2 B .0 C .1- D .2- 3.下面四个图形中,∠1=∠2一定成立的是( ). 4.下列图形分别是桂林、湖南、甘肃、佛山电视台的台徽,其中为中心对称图形的是( ). 5.下列运算正确的是( ). A. 22232x x x -= B .22(2)2a a -=- C .222()a b a b +=+ D .()2121a a --=-- 6.如图,已知Rt △ABC 中,∠C =90°,BC=3, AC=4, 则sinA 的值为( ).

A.3 4 B. 4 3 C. 3 5 D. 4 5 7.如图,图1是一个底面为正方形的直棱柱;现将图1切割成图2的几何体,则图2的俯视图是(). 8.直线1 y kx =-一定经过点(). A.(1,0) B.(1,k) C.(0,k) D.(0,-1) 9.下面调查中,适合采用全面调查的事件是(). A.对全国中学生心理健康现状的调查. B.对我市食品合格情况的调查. C.对桂林电视台《桂林板路》收视率的调查. D.对你所在的班级同学的身高情况的调查. 10.若点 P(a,a-2)在第四象限,则a的取值范围是(). A.-2<a<0 B.0<a<2 C.a>2 D.a<0 11.在平面直角坐标系中,将抛物线223 y x x =++绕着它与y轴的交点旋转180°,所得抛物线的解析式是(). A.2 (1)2 y x =-++ B.2 (1)4 y x =--+ C.2 (1)2 y x =--+ D.2 (1)4 y x =-++ 12.如图,将边长为a的正六边形A1 A2 A3 A4 A5 A6在直线l上由图1的位置按顺时针方 向向右作无滑动滚动,当A 1第一次滚动到图2位置时,顶点A 1 所经过的路径的 长为(). A.423 3 a π + B. 843 3 a π + C. 43 3 a π + D. 423 6 a π +

2012福建厦门中考数学

厦门市2012年初中毕业及高中阶段各类学校招生考试 数学试题 一、选择题 (本大题有 7 小题,每小题3分,共21分。每小题都有四个选项,其中有且只有一个选项是正确的) 1.(2012厦门,1,3分)-2的相反数是 ( ) A.2 B.-2 C.2± D. 1 2 - 答案:A. 2. (2012厦门,2,3分)下列事件中,是必然事件的是 ( ) A.抛掷 1 枚硬币,掷得的结果是正面朝上 B.抛掷 1 枚硬币,掷得的结果是反面朝上 C.抛掷 1 枚硬币,掷得的结果不是正面朝上就是反面朝上 D.抛掷 2 枚硬币,掷得的结果是 1 个正面朝上与 1 个反面朝上 答案:C. 3. (2012厦门,3,3分)图 1是一个立体图形的三视图,则这个立体图形是 ( ) A.圆锥 B.球 C. 圆柱 D. 三棱锥 答案:A. 4.(2012厦门,4,3分)某种彩票的中奖机会是 1%,下列说法正确的是 ( ) A.买一张这种彩票一定不会中奖 B. 买 1张这种彩票一定会中奖 C.买 100张这种彩票一定会中奖 D.当购买彩票的数量很大时,中奖的频率稳定在 1% 答案:D. 5.(2012厦门,5,3分)x的取值范围是() A.1 x> B.1 x≥ C. 1 x< D.1 x≤ 答案:B. 规律总结:二次根式有意义,令被开方数大于或大于0,转化为解不等式的问题.

关键词:二次根式 一元一次不等式 6. (2012厦门,6,3分)如图 2,在菱形ABCD 中,AC 、BD 是对角线,若∠BAC =50°,则∠ABC 等于 ( ) A.40° B.50° C.80° D.100° 答案:C . 7. (2012厦门,7,3分)已知两个变量x 和y ,它们之间的 3组对应值如下表所示 则y 与x 之间的函数关系式可能是 ( ) A.y x = B.21y x =+ C.21y x x =++ D.3y x = 答案:B . 二、填空题 (本大题有 10小题,每小题4分,共40分) 8. (2012厦门,8,4分)计算:32a a -= . 答案:a 9. (2012厦门,9,4分)已知∠A =40°,则∠A 的余角的度数是 . 答案:50°. 10. (2012厦门,10,4分)计算:32m m ÷= . 答案:m 11. (2012厦门,11,4分) 在分别写有整数 1 到 10 的 10张卡片中,随即抽取 1 张卡片,则该卡片的数字恰好是奇数的概率是 . 答案:12. 12. (2012厦门,12,4分)如图3,在等腰梯形ABCD 中,AD ∥BC ,对角线AC 与BD 相交于点O ,若OB =3,则 OC = .

2012年广东省中考数学试卷(解析版)

2012年广东省中考数学试卷 (含答案) 一、选择题(共5小题) 1.(2012广东)﹣5的绝对值是() A. 5 B.﹣5 C.D.﹣考点:绝对值。 解答:解:根据负数的绝对值等于它的相反数,得|﹣5|=5.故选A. 2.(2012广东)地球半径约为6400000米,用科学记数法表示为() A.0.64×107B. 6.4×106C. 64×105 D.640×104 考点:科学记数法—表示较大的数。 解答:解:6400000=6.4×106. 故选B. 3.(2012广东)数据8、8、6、5、6、1、6的众数是() A. 1 B. 5 C. 6 D.8 考点:众数。 解答:解:6出现的次数最多,故众数是6. 故选C. 4.(2012广东)如图所示几何体的主视图是() A.B.C.D.考点:简单组合体的三视图。 解答:解:从正面看,此图形的主视图有3列组成,从左到右小正方形的个数是:1,3,1.故选:B. 5.(2012广东)已知三角形两边的长分别是4和10,则此三角形第三边的长可能是()A. 5 B. 6 C.11 D.16 考点:三角形三边关系。

解答:解:设此三角形第三边的长为x,则10﹣4<x<10+4,即6<x<14,四个选项中只有11符合条件. 故选C. 二、填空题(共5小题) 6.(2012广东)分解因式:2x2﹣10x=2x(x﹣5). 考点:因式分解-提公因式法。 解答:解:原式=2x(x﹣5). 故答案是:2x(x﹣5). 7.(2012广东)不等式3x﹣9>0的解集是x>3. 考点:解一元一次不等式。 解答:解:移项得,3x>9, 系数化为1得,x>3. 故答案为:x>3. 8.(2012广东)如图,A、B、C是⊙O上的三个点,∠ABC=25°,则∠AOC的度数是50. 考点:圆周角定理。 解答:解:∵圆心角∠AOC与圆周角∠ABC都对, ∴∠AOC=2∠ABC,又∠ABC=25°, 则∠AOC=50°. 故答案为:50 9.(2012广东)若x,y为实数,且满足|x﹣3|+=0,则()2012的值是1. 考点:非负数的性质:算术平方根;非负数的性质:绝对值。 解答:解:根据题意得:, 解得:. 则()2012=()2012=1. 故答案是:1.

2014年中考数学模拟试题

2014年中考数学模拟试题 (满分120分 时间120分钟) 一.选择题(每小题3分,共30分) 1.-8的相反数是 A .8 B . -8 C . 81 D .8 1 2.中国航母辽宁舰是中国人民海军第一艘可以搭载固定翼飞机的航空母舰,满载排水量为67500吨.这个数据用科学记数法表示为 A .6.75×104 B .67.5×103 C . 0.675×105 D .6.75×10-4 3.下列运算正确的是( ) A .2a +3b = 5ab B .a 2·a 3=a 5 C .(2a) 3 = 6a 3 D .a 6+a 3= a 9 4.如图,AB ∥CD ,CE 平分∠BCD ,∠DCE=18°,则∠B 等于 A .18° B .36° C .45° D .54° 5.上图是一个几何体的三视图,这个几何体的名称是 A .圆柱体 B .三棱锥 C .球体 D .圆锥体 6.在“大家跳起来”的乡村学校舞蹈比赛中,某校10名学生参赛成绩统计如图所示. 对于这10名学生的参赛成绩,下列说法中错误的是 A .众数是90 B .中位数是90 C .平均数是90 D .极差是15 7.已知两圆的圆心距为4,两圆的半径分别是3和5,则这两圆的位置关系是 A. 内含 B. 内切 C. 外切 D. 相交 8.如图,在平面直角坐标系中,以O 为圆心,适当长为半径画弧,交x 轴 于点M ,交y 轴于点N ,再分别以点M 、N 为圆心,大于2 1MN 的长为半径 画弧,两弧在第二象限交于点P .若点P 的坐标为(2a ,b+1),则a 与 b 的数量关系为 A. a=b B. 2a+b=﹣1 C .2a ﹣b=1 D .2a+b=1 9.如图,一次函数与反比例函数的图象相交于A 、B 两点,则图中使反比 例函数的值小于一次函数的值的x 的取值范围是 A .x <-1 B .-1<x <0或x >2 C .x >2 D .x <-1或0<x <2 第4题图 第5题图 第6题图

2013年福建省厦门市数学中考真题(word版含答案)

2013年福建省厦门市初中毕业及高中阶段各类学校招生考试 数 学 (试卷满分:150分 考试时间:120分钟) 准考证号 姓名 座位号 注意事项: 1.全卷三大题,26小题,试卷共4页,另有答题卡. 2.答案一律写在答题卡上,否则不能得分. 3.可直接用2B 铅笔画图. 一、选择题(本大题有7小题,每小题3分,共21分.每小题都有四个选项,其中有且只有 一个选项正确) 1.下列计算正确的是 A .-1+2=1 B .-1-1=0 C .(-1)2=-1 D .-12=1 2.已知∠A=60°,则∠A 的补角是 A .160° B .120° C .60° D .30° 3.图1是下列一个立体图形的三视图,则这个立体图形是 A .圆锥 B .球 C .圆柱 D .正方体 4.掷一个质地均匀的正方体骰子,当骰子停止后,朝上一面的点数为5的概率是 A .1 B . 51 C .6 1 D .0 5.如图2,在圆O 中,弧AB=弧AC ,∠A=30°,则∠B= A .150° B .75° C .60° D .15°

6.方程 x x 3 12=-的解是 A .3 B .2 C .1 D .0 7.在平面直角坐标系中,将线段OA 向左平移2个单位,平移后,点O 、A 的对应点分别为点O 1、A 1,若O (0,0),A (1,4),则点O 1、A 1的坐标分别是 A .(0,0),(1,4) B .(0,0),(3,4) C .(-2,0),(1,4) D .(-2,0)(-1,4) 二、填空题(本大题有10小题,每小题4分,共40分) 8.-6的相反数是 9.计算:m 2·m 3= 10.式子3-x 在实数范围内有意义,则实数x 的取值范围是 11.如图3,在△ABC 中,DE ∥BC ,AD=1,AB=3,DE=2,则BC= 12.在一次中学田径运动会上,参加男子跳高的15名运动员的成绩如下表所示: 成绩/米 1.50 1.60 1.65 1.70 1.75 1.8 人数 2 3 3 2 4 1 则这些运动员成绩的中位数是 米. 13.x 2-4x +4=( )2 14.已知反比例函数x m y 1 -= 的图像的一支位于第一象限,则常数m 的取值范围是 15.如图4,平行四边形ABCD 的对角线AC ,BD 相交于点O ,点E ,F 分别是线段AO , BO 的中点,若AC+BD=24厘米,△OAB 的周长是18厘米,则EF= 厘米. 16.某采石场爆破时,点燃导火线的甲工人摇在爆破前转移到400米以外的安全区,甲工人在转移过程中,前40米只能步行,之后骑自行车,已知导火线燃烧的速度为0.01米/秒,步 行的速度为1米/秒,骑车的速度为4米/秒,为了确保加工人的安全,则导火线的长要大于 米. 17.如图5,在平面直角坐标系中,点O 是原点,点B (0,3),点A 在第一象限且AB ⊥BO ,点E 是线段AO 的中点,点M 在线段AB 上,若点B 和点E 关

2012年广东省中考数学模拟试题(四)及答案

2012年广东省中考全真模拟试题(四) 数学试卷 学校:__________班别:__________姓名:__________分数:____________ 说明:全卷共4页,考试用时100分钟,满分120分. 一、选择题(本大题5小题,每小题3分,共15分)在每小题列出的四个选项中,只有一 个是正确的. 1. 下列各式中与2是同类二次根式是( ) A B C D 2.已知点(,3)A a -是点(2,)B b -关于原点O 的对称点,则a +b 的值为( ) A 、6 B 、5- C 、5 D 、6± 3.下列汽车标志中,是中心对称图形的是( ) A. B. C D 4.用配方法解一元二次方程2430x x -+=时可配方得( ) A.2(2)7x -= B.2(2)1x -= C.2(2)1x += D.2(2)2x += 5.如图,O ⊙是ABC △的外接圆,已知50ABO ∠=°,则ACB ∠的大小为( ) A .40° B .30° C .45° D .50° 二、填空题(本大题5小题,每小题4分,共20分)请将下列各题的正确答案填在答题卡相应的位置上. 6 的平方根是 . 7.方程x (x -1)=2(x -1)的解为 . 8.如图2,⊙O 的直径为10,圆心O 到弦AB 的距离OM 的长为3,则弦AB 的长是 。 9.已知点P 到⊙O 的最近距离是3cm 、最远距离是7cm ,则此圆的半径是 。 (第5题) 图2

10.如图,PA 、PB 分别切⊙O 于A 、B ,PA=10cm ,C 是劣弧AB 是的 点(不与点A 、B 重合),过点C 的切线分别交PA 、PB 于点E 、F 。则△PEF 的周长为 . 三、解答题(一)(本大题5小题,每小题6分,共30分) 11. 计算: 20100(1)|(2-+- 12.解方程: x(x-2)+x-2=0 13.如图:在平面直角坐标系中,网格中每一个小 正方形的边长为1个单位长度;已知△ABC ① 将△ABC 向x 轴正方向平移5个单位得△A 1B 1C 1, ② 再以O 为旋转中心,将△A 1B 1C 1旋转180°得△A 2B 2C 2 画出平移和旋转后的图形,并标明对应字母. 14.求值: ()x x x x x 22 4 422+÷+++,其中x =2. 15.关于x 的一元二次方程2 30x x k --=有两个不相等的实数根. (1)求k 的取值范围. (2)请选择一个k 的负整数值,并求出方程的根.

厦门中考数学试卷及答案

2015年厦门市初中毕业及高中阶段各类学校招生考试 数学 (试卷满分:150分考试时间:120分钟) 准考证号姓名座位号 注意事项: 1.全卷三大题,27小题,试卷共4页,另有答题卡. 2.答案一律写在答题卡上,否则不能得分. 3.可直接用2B铅笔画图. 一、选择题(本大题有10小题,每小题4分,共40分.每小题都有四个选项, 其中有且只有一个选项正确) 1.反比例函数y=的图象是 A.线段B.直线C.抛物线D.双曲线 2.一枚质地均匀的骰子,骰子的六个面上分别刻有1到6的点数,投掷这样的骰 子一次,向上一面点数是偶数的结果有 A.1种 B.2种 C.3种D.6种 3.已知一个单项式的系数是2,次数是3 A.-2xy2 B.3x2 C.2xy3 D.2x3 4.如图1,△ABC是锐角三角形,过点C作CD⊥AB,垂足为D, 则点C到直线AB的距离是图1 A.线段CA的长 B.线段CD的长 C.线段AD的长 D.线段AB的长 5.2—3可以表示为 A.22÷25B.25÷22 C.22×25D.(-2)×(-2)×(-2) 6.如图2,在△ABC中,∠C=90°,点D,E分别在边AC,AB上,

若∠B=∠ADE,则下列结论正确的是 A.∠A和∠B互为补角 B.∠B和∠ADE互为补角 C.∠A和∠ADE互为余角D.∠AED和∠DEB互为余角 图2 7.某商店举办促销活动,促销的方法是将原价x元的衣服以(x-10)元出售,则下 列说法中,能正确表达该商店促销方法的是 A.原价减去10元后再打8折 B.原价打8折后再减去10元 C.原价减去10元后再打2折 D.原价打2折后再减去10元 8.已知sin6°=a,sin36°=b,则sin26°= A.a2 B.2a C.b2D.b 9.如图3,某个函数的图象由线段AB和BC A(0,),B(1,),C(2,),则此函数的最小值是 A.0B.C.1D.图3 10.如图4,在△ABC中,AB=AC,D是边BC A,交边AB于 点E,且与BC相切于点D,则该圆的圆心是 A.线段AE的中垂线与线段AC的中垂线的交点 B.线段AB的中垂线与线段AC的中垂线的交点 C.线段AE的中垂线与线段BC的中垂线的交点 D.线段AB的中垂线与线段BC的中垂线的交点 图4 二、填空题(本大题有6小题,每小题4分,共24分) 11.不透明的袋子里装有1个红球、1个白球,这些球除颜色外无其他差别.从袋子中随机 摸出一个球,则摸出红球的概率是. 12.方程x2+x=0的解是.

2013年广东省中考数学试卷(含解析版)

2013年广东省中考数学试卷 一、选择题(共10小题,每小题3分,满分30分) 1.(3分)2的相反数是() A.B.C.﹣2D.2 2.(3分)下列四个几何体中,俯视图为四边形的是() A.B.C.D. 3.(3分)据报道,2013年第一季度,广东省实现地区生产总值约1260 000 000 000元,用科学记数法表示为() A.0.126×1012元B.1.26×1012元C.1.26×1011元D.12.6×1011元4.(3分)已知实数a、b,若a>b,则下列结论正确的是() A.a﹣5<b﹣5B.2+a<2+b C.D.3a>3b 5.(3分)数字1、2、5、3、5、3、3的中位数是() A.1B.2C.3D.5 6.(3分)如图,AC∥DF,AB∥EF,点D、E分别在AB、AC上,若∠2=50°,则∠1的大小是() A.30°B.40°C.50°D.60° 7.(3分)下列等式正确的是() A.(﹣1)﹣3=1B.(﹣4)0=1 C.(﹣2)2×(﹣2)3=﹣26D.(﹣5)4÷(﹣5)2=﹣52 8.(3分)不等式5x﹣1>2x+5的解集在数轴上表示正确的是() A.B. C.D.

9.(3分)下列图形中,不是轴对称图形的是() A.B.C.D. 10.(3分)已知k1<0<k2,则函数y=k1x﹣1和y=的图象大致是()A.B. C.D. 二、填空题(本大题6小题,每小题4分,共24分)请将下列各题的正确答案填写在答题 卡相应位置上. 11.(4分)分解因式:x2﹣9=. 12.(4分)若实数a、b满足|a+2|,则=. 13.(4分)一个六边形的内角和是. 14.(4分)在Rt△ABC中,∠ABC=90°,AB=3,BC=4,则sin A=.15.(4分)如图,将一张直角三角形纸片ABC沿中位线DE剪开后,在平面上将△BDE绕着CB的中点D逆时针旋转180°,点E到了点E′位置,则四边形ACE′E的形状是. 16.(4分)如图,三个小正方形的边长都为1,则图中阴影部分面积的和是(结果保留π).

2014中考数学模拟试题(新考点必考题型) (80)

A B C E D F A B C C 1 B 1 A O B C D E 中考数学全真模拟试卷 考生注意:1、考试时间 120分钟 2、全卷共三大题,总分 120 分 一、选择题(每小题3分,共30分) 1.下列运算中,正确的个数是( ) () 32352 6023215x x x x x +==?-=①,②,③,④538--+=,⑤11212 ÷=·. A .1个 B .2个 C .3个 D .4个 2.现有四条线段,长度依次是2,3,4,5,从中任选三条,能组成三角形的概率是( ) A .34 B .13 C .12 D .2 3 3.某年,某地区春季共植树0.024亿棵,0.024亿用科学记数法表示为( ) A .24×105 B .2.4×105 C .2.4×106 D .0.24×109 4.在Rt △ABC 中,∠C =90o,BC =4cm ,AC =3cm .把△ABC 绕点A 顺时针旋转90o后,得到△AB 1C 1,如图所示,则点B 所走过的路径长为( ) A .52cm B . 5 4πcm C . 5 2πcm D .5πcm 5.若关于x 的一元二次方程mx 2―2x ―1=0无实数根,则一次函数y =(m +1)x -m 的图象不经过( ) A .第一象限 B .第二象限 C .第三象限 D .第四象限 6.如图,是一个几何体的三视图,根据图中标注的数据可求得这个几何体的体积为( ) A .24π B .32π C .36π D .48π 7.在44?的正方形网格中,已将图中的四个小正方形涂上阴影(如图),若再从其余小 正方形中任选一个也涂上阴影,使得整个阴影部分组成的图形成轴对称图形.那么符合条件的小正方形共有( ) A .1个 B .2个 C .3个 D .4个 8.如图,AC 是矩形ABCD 的对角线,E 是边BC 延长线上一点, AE 与CD 交于点F ,则图中相似三角形共有( ) A .2对 B .3对 C .4对 D .5对 9.某班体育委员调查了本班46名同学一周的平均 每天体育活动时间,并制作了如图所示的频数分布直方图,从直方图中可以看出,该班同学这一周平均每天体育活动时间的中位数和众数 依次是( ) A .40分,40分 B .50分,40分 C .50分,50分 D .40分,50分 10.如图,已知AB 是⊙O 的直径,⊙O 交BC 的中点于D ,DE ⊥AC 于E ,连接AD ,则下列结论正确的个数是( ) ①AD ⊥BC ,②∠EDA =∠B ,③OA = 1 2AC ,④DE 是⊙O 的切线. A .1个 B .2个 C .3个 D .4个 二、填空题(每小题3分,共24分) 11.计算0 3 11 (1)3tan 30(2)()4π---+-?= . 12. 如图,点A 、B 是双曲线3 y x =上的点,分别经过A 、 B 两点向x 轴、y 轴作垂线段,若1S =阴影, 则12S S += . 6 4 主视图 左视图 俯视图 6 4 4 (6题图) (7题图) 频数(人) 时间(分) 20 10 30 40 50 60 70 2 0 6 9 14 某班46名同学一周平均每天体育 活动时间频数分布直方图 (第9题) x y A B O 12题图

厦门中考数学试卷及答案

模拟试卷 一、选择题(本大题有7小题,每小题3分,共21分。每小题都有四个选项,其中有且只有一个选项是正确的) 1.化简|2|-等于( ) A .2 B . 2- C .2± D .12 2.下列事件中,必然事件是( ) A .掷一枚普通的正方体骰子,骰子停止后朝上的点数是1 B . 掷一枚普通的正方体骰子,骰子停止后朝上的点数是偶数 C . 掷一枚普通的硬币,掷得的结果不是正面就是反面 D . 从99个红球和一个白球的布袋中随机取出一个球,这个球是红球 3.下列物体中,俯视图为矩形的是( ) A . B . C . D . 4.下列计算结果正确的是( ) A .2a a a ?= B .2 2 (3)6a a = C .22 (1)1a a +=+ D .2 a a a += 5.如图1,在正方形网格中,将△ABC 绕点A 旋转后得到△ADE ,则下列旋转方式中,符合题意的是( ) A .顺时针旋转90° B .逆时针旋转90° C .顺时针旋转45° D .逆时针旋转45° 6.已知⊙O 1,和⊙O 2的半径分别为5和2,O 1 O 2=3,则⊙O 1,和⊙O 2的位置关系是( ) A .外离 B .外切 C .相交 D .内切 7. 如图2,铁道口的栏杆短臂OA 长1m ,长臂OB 长8m ,当短臂外端A 下降0.5m 时,长臂外端B 升高( ) A .2m B .4m C .4.5 D .8m

图1 图2 二、填空题(本大题有10小题,每小题4分,共40分) 8.1 3 的相反数是。 9.若∠A=30°,则∠A的补角是。 10.将1 200 000用科学记数法表示为。 11.某年6月上旬,厦门市日最高气温气温如下表所示: 那么这些日最高气温的众数为℃ 12.一个n边行的内角和是720°,则边数n= 。 13.如图3,⊙O的直径CD垂直于弦AB,垂足为E,若AB=6cm,则AE= cm. 14.Rt△ABC中,若∠C=90°,AC=1,AB=5,则sin B= . 15.已知一个圆锥的底面半径长为3cm,母线长为6cm,则圆锥的侧面积是cm2. 16.如图4,正方形网格中,A、D、B、C都在格点上,点E是线段AC上的任意一点,若AD=1, 那么AE= 时,以点A、D、E为顶点的三角形与△ABC相似。 17.如图5中的一系列“黑色梯形”,是由x轴、直线y=x和过x轴上的正奇数1,3,5,

2012年广东省中考数学试卷及解析

机密★启用前 2012年广东省初中毕业生学业考试 数 学 说明:1.全卷共4页,考试用时100分钟,满分为120分. 2.答卷前,考生务必用黑色字迹的签字笔或钢笔在答题卡填写自己的准考证号、姓名、 试室号、座位号.用2B 铅笔把对应该号码的标号涂黑. 3.选择题每小题选出答案后,用2B 铅笔把答题卡上对应题目选项的答案信息点涂黑, 如需改动,用像皮檫干净后,再选涂其他答案,答案不能答在试题上. 4.非选择题必须用黑色字迹钢笔或签字笔作答、答案必须写在答题卡各题目指定区域 内相应位置上;如需改动,先划掉原来的答案,然后再写上新的答案;不准使用铅 笔和涂改液.不按以上要求作答的答案无效. 5.考生务必保持答题卡的整洁.考试结束时,将试卷和答题卡一并交回. 一、选择题(本大题5小题,每小题3分,共15分)在每小题列出的四个选项中,只有一个是正确的,请把答 题卡上对应题目所选的选项涂黑. 1. —5的相反数是( A ) A. 5 B. —5 C. 51 D. 5 1- 2. 地球半径约为6 400 000米,用科学记数法表示为( B ) A. 0.64×107 B. 6.4×106 C. 64×105 D. 640×104 3. 数据8、8、6、5、6、1、6的众数是( C ) A. 1 B. 5 C. 6 D. 8 4. 如左图所示几何体的主视图是( B ) 5. 已知三角形两边的长分别是4和10,则此三角形第三边的长可能是( C ) A. 5 B. 6 C. 11 D. 16 二、填空题(本大题5小题,每小题4分,共20分)请将下列各题的正确答案填写在答题卡相应的位置上. 6. 分解因式:2x 2 —10x = 2x (x —5) . 7. 不等式3x —9>0的解集是 x>3 . 8. 如图,A 、B 、C 是⊙O 上的三个点,∠ABC = 250, 则∠AOC 的度数是 500 . 9. 若x 、y 为实数,且满足033=++ -y x ,则2012 ? ?? ? ??y x 的值是 1 . 10. 如图,在□ABCD 中,AD =2,AB =4,∠A =300,以点A 为圆心,AD 的长为半径画弧交AB 于点E,连结CE,则 A. B. C. D 题4图 A B C O 题8图 250

2014中考数学模拟试题(新考点必考题型)

最新中考数学全真模拟试题 (本试卷满分120分,考试时间120分钟) 第Ⅰ卷 (选择题 共36分) 一、选择题:(本大题共12小题,每小题3分,共36分) 1.(—6)0的相反数等于( ) A .1 B .—1 C .6 D .—6 2.已知点M (a ,3)和点N (4,b )关于y 轴对称,则(b a +)2012的值为( ). A .1 B .一l C .72012 D .一72012 3.下列运算正确的是( ). A .a a a =-23 B .6 32a a a =? C .326 ()a a = D .()3 3 93a a = 4. 下列图形中既是轴对称图形又是中心对称图形的是( ). A. B . C . D . 5. 下列数中:6、 2 π 、23.1、722、36-,0.333…、1.212112 、1.232232223… (两个3之间依次多一个2);无理数的个数是( ) A .2个 B .3个 C .4个 D .5个 6.如图是由一些完全相同的小立方块搭成的几何体的三种视图,那么搭成这个几何体所用的小立方块的个数是 ( ) A .5个 B .6个 C .7个 D .8个 7.不等式211 841x x x x -≥+?? +≤-? 的解集是( ). A .3x ≥ B .2x ≥ C .23x ≤≤ D .空集 8.某次有奖竞答比赛中,10名学生的成绩统计如下:

则下列说明正确的是( ). A .学生成绩的极差是2 B .学生成绩的中位数是2 C .学生成绩的众数是80分 D .学生成绩的平均分是70分 9.如图,AB CD ∥,下列结论中正确的是( ) A .123180++= ∠∠∠ B .123360++= ∠∠∠ C .1322+=∠∠∠ D .132+=∠∠∠ 10.已知反比例函数5 m y x -=的图象在第二、四象限,则m 取值范围是( ) A . m >5 B .m<5 C .m ≥5 D .m >6 _ 11. 下列从左到右的变形是因式分解的是( ) A .(x+1)(x-1)=x 2-1 B .(a-b )(m-n )=(b-a )(n-m ) C .ab-a-b+1=(a-1)(b-1) D .m 2-2m-3=m (m-2- m 3 ) 12.如图,正方形ABCD 的边长为4,P 为正方形边上一动点,运动路线是A →D →C →B →A ,设P 点经过的路程为x ,以点A 、P 、D 为顶点的三角形的面积是y .则下列图象能大致反映y 与x 的函数关系的是( ).

福建省厦门市2014年中考数学试卷及答案【Word版】

2014年福建省厦门市中考数学试卷 一、选择题(本大题共7小题,每小题3分,共21分) 1.(3分)(2014年福建厦门)sin30°的值是() A.B. C. D. 1 分析:直接根据特殊角的三角函数值进行计算即可. 解答:解:sin30°=. 故选A. 点评:本题考查的是特殊角的三角函数值,熟记各特殊角度的三角函数值是解答此题的关键. 2.(3分)(2014年福建厦门)4的算术平方根是() A.16 B. 2 C.﹣2 D.±2 考点:算术平方根. 分析:根据算术平方根定义求出即可. 解答:解:4的算术平方根是2, 故选B. 点评:本题考查了对算术平方根的定义的应用,主要考查学生的计算能力. 3.(3分)(2014年福建厦门)3x2可以表示为() A.9x B.x2?x2?x2C.3x?3x D. x2+x2+x2 考点:单项式乘单项式;合并同类项;同底数幂的乘法. 专题:计算题. 分析:各项计算得到结果,即可做出判断. 解答:解:3x2可以表示为x2+x2+x2, 故选D 点评:此题考查了单项式乘以单项式,合并同类项,以及同底数幂的乘法,熟练掌握运算法则是解本题的关键. 4.(3分)(2014年福建厦门)已知直线AB,CB,l在同一平面内,若AB⊥l,垂足为B,CB⊥l,垂足也为B,则符合题意的图形可以是() A.B.C.D. 考点:垂线. 分析:根据题意画出图形即可.

解答:解:根据题意可得图形, 故选:C. 点评:此题主要考查了垂线,关键是掌握垂线的定义:当两条直线相交所成的四个角中,有一个角是直角时,就说这两条直线互相垂直,其中一条直线叫做另一条直线的垂线,它们的交点叫做垂足. 5.(3分)(2014年福建厦门)已知命题A:任何偶数都是8的整数倍.在下列选项中,可以作为“命题A是假命题”的反例的是() A.2k B.15 C.24 D.42 考点:命题与定理. 分析:证明命题为假命题,通常用反例说明,此反例满足命题的题设,但不满足命题的结论. 解答:解:42是偶数,但42不是8的倍数. 故选D. 点评:本题考查了命题:判断一件事情的语句,叫做命题.许多命题都是由题设和结论两部分组成,题设是已知事项,结论是由已知事项推出的事项,一个命题可以写成“如果…那么…”形式;有些命题的正确性是用推理证实的,这样的真命题叫做定理. 6.(3分)(2014年福建厦门)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.∠EDB B.∠BED C.∠AFB D. 2∠ABF 考点:全等三角形的判定与性质. 分析:根据全等三角形的判定与性质,可得∠ACB与∠DBE的关系,根据三角形外角的性质,可得答案. 解答:解:在△ABC和△DEB中, , ∴△ABC≌△DEB (SSS), ∴∠ACB=∠DEB.

2012年广东省中考数学试卷及详细参考答案

2012年广东省中考数学试卷 一、选择题(本大题共5小题,每小题3分,共15分)在每个小题列出的四个选项中,只有一个是正确的,请把答题卡上对应题目所选的选项涂黑. 1.(2012?广东)﹣5的绝对值是() A. 5 B.﹣5 C.D.﹣ 2.(2012?广东)地球半径约为6400000米,用科学记数法表示为() A.0.64×107B.6.4×106C.64×105D.640×104 3.(2012?广东)数据8、8、6、5、6、1、6的众数是() A.1B.5C.6D.8 4.(2012?广东)如图所示几何体的主视图是() A.B.C.D. 5.(2012?广东)已知三角形两边的长分别是4和10,则此三角形第三边的长可能是() A.5B.6C.11 D.16 二、填空题(每小题4分,共20分)请将下列各题的正确答案填写在答题卡相应的位置上.6.(2012?广东)分解因式:2x2﹣10x=_________. 7.(2012?广东)不等式3x﹣9>0的解集是_________. 8.(2012?广东)如图,A、B、C是⊙O上的三个点,∠ABC=25°,则∠AOC的度数是_________. 9.(2012?广东)若x,y为实数,且满足|x﹣3|+=0,则()2012的值是_________. 10.(2012?广东)如图,在?ABCD中,AD=2,AB=4,∠A=30°,以点A为圆心,AD的长为半径画弧交AB于点E,连接CE,则阴影部分的面积是_________(结果保留π).

三、解答题(一)(每小题6分,共30分) 11.(2012?广东)计算:﹣2sin45°﹣(1+)0+2﹣1. 12.(2012?广东)先化简,再求值:(x+3)(x﹣3)﹣x(x﹣2),其中x=4. 13.(2012?广东)解方程组:. 14.(2012?广东)如图,在△ABC中,AB=AC,∠ABC=72°. (1)用直尺和圆规作∠ABC的平分线BD交AC于点D(保留作图痕迹,不要求写作法); (2)在(1)中作出∠ABC的平分线BD后,求∠BDC的度数. 15.(2012?广东)已知:如图,在四边形ABCD中,AB∥CD,对角线AC、BD相交于点O,BO=DO.求证:四边形ABCD是平行四边形. 四、解答题(二)(本大题共4小题,每小题7分,共28分) 16.(2012?广东)据媒体报道,我国2009年公民出境旅游总人数约5000万人次,2011年公民出境旅游总人数约7200万人次,若2010年、2011年公民出境旅游总人数逐年递增,请解答下列问题:(1)求这两年我国公民出境旅游总人数的年平均增长率;

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