圆锥曲线高考真题专练(含答案)

(一)数学全国1卷

设椭圆22:12xCy的右焦点为F,过F的直线l与C交于,AB两点,点M的坐标为(2,0).

(1)当l与x轴垂直时,求直线AM的方程;

(2)设O为坐标原点,证明:OMAOMB.

解:(1)由已知得(1,0)F,l的方程为x=1.

由已知可得,点A的坐标为2(1,)2或2(1,)2.

所以AM的方程为222yx或222yx.

(2)当l与x轴重合时,0OMAOMB.

当l与x轴垂直时,OM为AB的垂直平分线,所以OMAOMB.

当l与x轴不重合也不垂直时,设l的方程为(1)(0)ykxk,1221(,),(,)AyxyxB,

则122,2xx,直线MA,MB的斜率之和为212122MAMBxxyykk.

由1122,ykkxykxk得

121212(23()42)(2)MAMBxxxxkkxxkkk.

将(1)ykx代入2212xy得

2222(21)4220kxkxk.

所以,21221222422,2121xxxkkkxk.

则3131322244128423()4021kkkkkkkkkxxxx.

从而0MAMBkk,故MA,MB的倾斜角互补,所以OMAOMB. 综上,OMAOMB.

已知椭圆C:2222=1xyab(a>b>0),四点P1(1,1),P2(0,1),P3(–1,32),P4(1,32)中恰有三点在椭圆C上.

(1)求C的方程;

(2)设直线l不经过P2点且与C相交于A,B两点.若直线P2A与直线P2B的斜率的和为–1,证明:l过定点.

解:

(1)由于3P,4P两点关于y轴对称,故由题设知C经过3P,4P两点.

又由222211134abab知,C不经过点P1,所以点P2在C上.

因此222111314bab,解得2241ab.

故C的方程为2214xy.

(2)设直线P2A与直线P2B的斜率分别为k1,k2,

如果l与x轴垂直,设l:x=t,由题设知0t,且||2t,可得A,B的坐标分别为(t,242t),(t,242t).

则22124242122ttkktt,得2t,不符合题设.

从而可设l:ykxm(1m).将ykxm代入2214xy得

222(41)8440kxkmxm

由题设可知22=16(41)0km.

设A(x1,y1),B(x2,y2),则x1+x2=2841kmk,x1x2=224441mk. 而12121211yykkxx

121211kxmkxmxx

1212122(1)()kxxmxxxx.

由题设121kk,故1212(21)(1)()0kxxmxx.

即222448(21)(1)04141mkmkmkk.

解得12mk.

当且仅当1m时,0,欲使l:12myxm,即11(2)2myx,

所以l过定点(2,1)

数学全国1卷

设圆222150xyx的圆心为A,直线l过点B(1,0)且与x轴不重合,l交圆A于C,D两点,过B作AC的平行线交AD于点E.

(I)证明EAEB为定值,并写出点E的轨迹方程;

(II)设点E的轨迹为曲线C1,直线l交C1于M,N两点,过B且与l垂直的直线与圆A交于P,Q两点,求四边形MPNQ面积的取值范围.

【答案】(I)13422yx(0y);(II))38,12[

【解析】

试题分析:(I)利用椭圆定义求方程;(II)把面积表示为关于斜率k的函数,再求最值。

试题解析:(I)因为||||ACAD,ACEB//,故ADCACDEBD,

所以||||EDEB,故||||||||||ADEDEAEBEA.

又圆A的方程为16)1(22yx,从而4||AD,所以4||||EBEA.

由题设得)0,1(A,)0,1(B,2||AB,由椭圆定义可得点E的轨迹方程为: 4/54 13422yx(0y).

(II)当l与x轴不垂直时,设l的方程为)0)(1(kxky,),(11yxM,),(22yxN.

由134)1(22yxxky得01248)34(2222kxkxk.

则3482221kkxx,341242221kkxx.

所以34)1(12||1||22212kkxxkMN.

过点)0,1(B且与l垂直的直线m:)1(1xky,A到m的距离为122k,所以

1344)12(42||22222kkkPQ.故四边形MPNQ的面积

341112||||212kPQMNS.

可得当l与x轴不垂直时,四边形MPNQ面积的取值范围为)38,12[.

当l与x轴垂直时,其方程为1x,3||MN,8||PQ,四边形MPNQ的面积为12.

综上,四边形MPNQ面积的取值范围为)38,12[.

数学全国1卷

已知圆M:22(1)1xy,圆N:22(1)9xy,动圆P与圆M外切并且与圆N内切,圆心P的轨迹为曲线 C.

(Ⅰ)求C的方程;

(Ⅱ)l是与圆P,圆M都相切的一条直线,l与曲线C交于A,B两点,当圆P的半径最长时,求|AB|.

【解析】由已知得圆M的圆心为M(-1,0),半径1r=1,圆N的圆心为N(1,0),半径2r=3.

设动圆P的圆心为P(x,y),半径为R. (Ⅰ)∵圆P与圆M外切且与圆N内切,∴|PM|+|PN|=12()()RrrR=12rr=4,

由椭圆的定义可知,曲线C是以M,N为左右焦点,场半轴长为2,短半轴长为3的椭圆(左顶点除外),其方程为221(2)43xyx.

(Ⅱ)对于曲线C上任意一点P(x,y),由于|PM|-|PN|=22R≤2,∴R≤2,

当且仅当圆P的圆心为(2,0)时,R=2.

∴当圆P的半径最长时,其方程为22(2)4xy,

当l的倾斜角为090时,则l与y轴重合,可得|AB|=23.

当l的倾斜角不为090时,由1r≠R知l不平行x轴,设l与x轴的交点为Q,则||||QPQM=1Rr,可求得Q(-4,0),∴设l:(4)ykx,由l于圆M相切得2|3|11kk,解得24k.

当k=24时,将224yx代入221(2)43xyx并整理得27880xx,解得1,2x=4627,∴|AB|=2121||kxx=187.

当k=-24时,由图形的对称性可知|AB|=187,

综上,|AB|=187或|AB|=23.

数学全国1卷

设抛物线22(0)Cxpyp:的焦点为F,准线为l,A为C上一点,已知以F为圆心,FA为半径的圆F交l于,BD两点.

(1) 若90BFD,ABD的面积为42,求p的值及圆F的方程;

(2) 若,,ABF三点在同一直线m上,直线n与m平行,且n与C之有一个公共点,求坐标原点到,mn距离的比值.

【解析】(1)由对称性知:BFD是等腰直角,斜边2BDp 6/54 点A到准线l的距离2dFAFBp

1424222ABDSBDdp

圆F的方程为22(1)8xy

(2)由对称性设2000(,)(0)2xAxxp,则(0,)2pF

点,AB关于点F对称得:22220000(,)3222xxpBxppxppp

得:3(3,)2pAp,直线3322:30223ppppmyxxyp

22332233xxxpyyyxppp切点3(,)36ppP

直线333:()306336ppnyxxyp

坐标原点到,mn距离的比值为33:326pp。

已知O为坐标原点,F为椭圆C:2212yx在y轴正半轴上的焦点,过F且斜率为2的直线l与C交与A、B两点,点P满足0OAOBOP.

(I)证明:点P在C上;

(II)设点P关于点O的对称点为Q,证明:A、P、B、Q四点在同一圆上.

【命题意图】本题考查直线方程、平面向量的坐标运算、点与曲线的位置关系、曲线交点坐标求法及四点共圆的条件。

【解析】(I)(0,1)F,l的方程为21yx,代入2212yx并化简得

242210xx. …………………………2分

设112233(,),(,),(,)AxyBxyPxy, 则122626,,44xx

1212122,2()21,2xxyyxx

由题意得3123122(),()1,2xxxyyy

所以点P的坐标为2(,1)2.

经验证点P的坐标2(,1)2满足方程2212yx,故点P在椭圆C上…6分

(II)由P2(,1)2和题设知,Q2(,1)2,PQ的垂直平分线1l的方程为

22yx. ①

设AB的中点为M,则21(,)42M,AB的垂直平分线2l的方程为

2124yx. ②

由①、②得1l、2l的交点为21(,)88N. …………………………9分

22221311||()(1)2888NP,

22132||1(2)||2ABxx,

32||4AM,

22221133||()()48288MN,

22311||||||8NAAMMN, 8/54 故||||NPNA,

又||||NPNQ, ||||NANB,

所以||||||||NANPNBNQ,

由此知A、P、B、Q四点在以N为圆心,NA为半径的圆上.……………12分

如图,已知抛物线2:Eyx与圆222:(4)(0)Mxyrr相交于A、B、C、D四个点。

(I)求r得取值范围;

(II)当四边形ABCD的面积最大时,求对角线AC、BD的交点P坐标

分析:(I)这一问学生易下手。将抛物线2:Eyx与圆222:(4)(0)Mxyrr的方程联立,消去2y,整理得227160xxr.............(*)

抛物线2:Eyx与圆222:(4)(0)Mxyrr相交于A、B、C、D四个点的充要条件是:方程(*)有两个不相等的正根即可.易得15(,4)2r.考生利用数形结合及函数和方程的思想来处理也可以.

(II)考纲中明确提出不考查求两个圆锥曲线的交点的坐标。因此利用设而不求、整体代入的方法处理本小题是一个较好的切入点.

设四个交点的坐标分别为11(,)Axx、11(,)Bxx、22(,)Cxx、22(,)Dxx。

则由(I)根据韦达定理有212127,16xxxxr,15(,4)2r

则2112211212||()||()2Sxxxxxxxx

222212121212[()4](2)(7216)(415)Sxxxxxxxxrr

令216rt,则22(72)(72)Stt下面求2S的最大值。

方法一:利用三次均值求解。三次均值目前在两纲中虽不要求,但在处理一些最值问题有时很方便。它的主要手段是配凑系数或常数,但要注意取等号的条件,这和二次均值类似。

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高考英语完形填空专练含答案

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完型填空名校题目锦集专练

Cloze 1

(2017·安徽合肥高三第一次教学质量检测)

After stepping out of the international plane, I realized my

10-hour sleepy voyage finally came to an end. Sitting on the bus, I

was waiting anxiously for it to start.

A woman, sitting next to me, and her daughter both seemed

__1__. She told me that her daughter had an upset stomach and

would throw up continuously; __2__, the mother had lost her

__3__. Apart from a significant amount of money, the purse also had

her phone and a phone number of an important __4__, a person she

was travelling 90 kilometers to meet for discussing a __5__ matter

which had to be __6__ by tomorrow morning.

I handed her my cellphone without __7__ and told her that she

could make any call she wanted. I also __8__ a bottle of water I

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历年高考理科数学真题分类汇编之圆锥曲线含解析答案

历年高考理科数学真题分类汇编之圆锥曲线含解析答案

历年高考理科数学真题分类汇编之圆锥曲线(含解析答案)

一、选择填空

【2021新课标】7. 设直线l过双曲线C的一个核心,且与C的一条对称轴垂直,l与C交于 A,B两点,AB为C的实轴长的2倍,则C的离心率为( B )

(A)2 (B)3 (C)2 (D)3

【2021新课标】14. 在平面直角坐标系xOy中,椭圆C的中心为原点,核心12,FF在

x轴上,离心率为22。过l的直线 交于,AB两点,且 △ABF2的周长为16,那么C的方程为 221168xy 。

【2021新课标】4. 设是椭圆2222:1(0)xyEabab的左、右核心,P为直线上一点, 是底角为的等腰三角形,则E的离心率为( C )

()A12 ()B 23 ()C ()D

【解析】 是底角为的等腰三角形221332()224cPFFFaccea

【2021新课标】8. 等轴双曲线C的中心在原点,核心在x轴上,C与抛物线xy162的准线交于,AB两点,43AB;则C的实轴长为( C )

()A2 ()B 22 ()C ()D 12FF32ax21FPF3021FPF30【解析】设222:(0)Cxyaa交xy162的准线:4lx于(4,23)A(4,23)B

得:222(4)(23)4224aaa

【2021新课标1】4. 已知双曲线C:x2a2-y2b2=1(a>0,b>0)的离心率为4,则C的渐近线方程为( C )

A、y=±x (B)y=±Error! Cannot insert return character.x (C)y=±x (D)y=±x

语法专项技能:高考英语特殊句式句型真题专练含答案100题_百.

语法专项技能:高考英语特殊句式句型真题专练含答案100题_百.

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编写:李老师

1.---Who is the man talking to the headmaster?

---A professor__________ a visit to our school.

A. pays B. is paying C. paid D. paying

2. ---Does he like music? ---__________.

A. Don’t as I knowB. Don’t as far as I knowC. Not as I know D. Not as far as I

know

3. ---Do you think it’s going to rain over the weekend?

---_____________.

A. I don’t believeB. I don’t believe itC. I believe not so D. I believe not

4. ---Peter likes playing football, but he can’t play it well.

---_____________.

A. So does his brother B. Nor does his brother C. So is his brother D. It’s the same

with his brother 5. No sooner________ begun to speak_________ I sensed that

something was wrong.

A. he has; when B. he had; than C. had he; than D. did he; when

6. In recent years travel companies have succeeded in selling us the idea that the

2020高考英语语法填空考点专练(含答案)

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1 高考英语语法填空考点练习题

一.介词填空

1. We didn’t begin to watch TV_______________9:00.

2. He has been sick_______________yesterday.

3. He will be back_______________ five hours.

4. They cut the wood _______________a knife.

5. The old men were walking_______________ the river.

6. _______________short, he is one of the most promising students I’ve ever

known.

7. They paid an extra five percent in addition_______________ the price.

8. She learned Japanese_______________ her stay in Shanghai.

9. You can use that glass_______________ a vase.

10. _______________his arrival at the airport, the film star was recognized and soon

surrounded by a group of fans.

二.名词的数

1. Those ____________________(passer-by) witnessed the traffic accident.

2. Sugar is bad for your____________________(tooth).

3. He tore all the ____________________(photo) into pieces.

2013高考题非谓语动词专练(含答案)

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2013年高考题 非谓语动词专练

1. They might just have a place ___ on the writing course — why don’t you give it a

try?(新课标1)

A. leave B. left C. leaving D. to leave

2. The witnesses by the police just now gave very different descriptions of the

fight.(陕西)

A. questioned B. being questioned C. to be questioned D. having

questioned

3.I got to the office earlier that day, the 7:30 train from Paddington.(新课标2)

A. caught B. to have caught C. to catch D. having caught

4. The sunlight is white and blinding, ____ hard-edged shadows on the ground.(新课标1)

A. throwing B. being thrown C. to throw D. to be thrown

5. in the early 20th century, the school keeps on inspiring children’s love

of art.(安徽)

A. To found B. Founding

C. Founded D. Having founded

高考英语真题(含答案)

高考英语真题(含答案)

普通高等学校招生全国统一考试(全国卷I)

英 语

注意事项:

1.答卷前,考生务必将自己的姓名、准考证号填写在答题卡上。

2.回答选择题时,选出每小题答案后,用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,再选涂其他答案标号。回答非选择题时,将答案写在答题卡上,写在本试卷上无效。

3.考试结束后,将本试卷和答题卡一并交回。

第一部分 听力(共两节,满分30分)

做题时,先将答案标在试卷上。录音内容结束后,你将有两分钟的时间将试卷上的答案转涂到答题卡上。

第一节 (共5小题;每小题1.5分,满分7.5分)

听下面5段对话。每段对话后有一个小题,从题中所给的A、B、C三个选项中选出最佳选项。听完每段对话后,你都有10秒钟的时间来回答有关小题和阅读下一小题。每段对话仅读一遍。

例:How much is the shirt?

A. £19.15. B. £9.18. C. £9.15.

答案是C。

1.Where does this conversation take place?

A. In a classroom. B. In a hospital. C.In a museum.

2.What does Jack want to do?

A. Take fitness classes.

B. Buy a pair of gym shoes.

C. Change his work schedule.

3.What are the speakers talking about?

A. What to drink. B. Where to meet. C. When to leave.

4.What is the relationship between the speakers?

A. Colleges. B. Classmates. C. Strangers.

北京高考英语真题含答案

精品文档

. 2018年高考英语真题卷(北京卷)

一、单项填空

1.(2018?北京)—Hi, I'm Peter. Are you new here? I haven't seen you around?—Hello, Peter. I'm

Bob. I just _________ on Monday.

A. start B. have started C. started D. had started

2.(2018?北京)_________ we don't stop climate change, many animals and plants in the world will

be gone.

A.Although

B.While

C.If

D.Until

3.(2018?北京)_________ along the old Silk Road is an interesting and rewarding experience.

A. Travel B. Traveling C. Having

traveled D. Traveled

4.(2018?北京)Susan had quit her well-paid job and _________ as a volunteer in the neighborhood

when I visited her last year.

A. is working B. was working C. has worked D. had worked

5.(2018?北京)She and her family bicycle to work, _________ helps them keep fit.

A. which B. who C. as D. that

6.(2018?北京)During the Mid-Autumn Festival, family members often gather together _________

2020届高考物理专练:恒定电流(含答案)

2020届高考物理专练:恒定电流(答案在最后)

专题:恒定电流

一、选择题

1、如图所示,甲、乙、丙三个逻辑电路的符号分别表示(

)

A. “与”门、“或”门、“非”门

B. “与”门、“非”门、“或”门

C. “或”门、“与”门、“非”门

D. “或”门、“非”门、“与”门

2、阻值相等的四个电阻、电容器C及电池E(内阻可忽略)连接成如图所示电路.开关S断开且电流稳定时,C所带的电荷量为Q1;闭合开关S,电流再次稳定后,C所带的电荷量为Q2.Q1与Q2的比值为(

)

A.25 B.12

C.35 D.23

3、某一导体的伏安特性曲线如图AB段(曲线)所示,关于导体的电阻,以下说法正确的是(

)

A.B点的电阻为12 Ω

B.B点的电阻为40 Ω

C.导体的电阻因温度的影响改变了1 Ω D.导体的电阻因温度的影响改变了9 Ω

4、如图所示,其中电流表A的量程为 0.6 A,表盘均匀划分为30个小格,每一小格表示0.02 A;R1的阻值等于电流表内阻的12;R2的阻值等于电流表内阻的2倍.若用电流表A的表盘刻度表示流过接线柱1 的电流值,则下列分析正确的是(

)

A.将接线柱1、2接入电路时,每一小格表示0.04 A

B.将接线柱1、2接入电路时,每一小格表示0.02 A

C.将接线柱1、3接入电路时,每一小格表示0.06 A

D.将接线柱1、3接入电路时,每一小格表示0.01 A

5、如图所示的电路,R1、R2、R4均为定值电阻,R3为热敏电阻(温度升高,电阻减小),电源的电动势为E,内阻为r.起初电容器中悬停一质量为m的带电尘埃,当环境温度降低时,下列说法中正确的是(

)

A.电压表和电流表的示数都减小

B.电压表和电流表的示数都增大

C.电压表和电流表的示数变化量之比保持不变

D.带电尘埃将向下极板运动

6、如图所示的电路中,闭合开关后各元件处于正常工作状态,当某灯泡突然出现故障时,电流表读数变小,电压表读数变大.下列关于故障原因或故障后其他物理量的变化情况的说法中正确的是(

高考英语阅读七选五专练含答案

阅读七选五专练(一)

A

(2016·兰州市高三诊断考试)People need homes: children assume their parents' place as

home; boarders call school “home” on weekdays; married couples work together to build new

homes; and travelers ... have no place to call “home”, at least for a few nights.

__1__?Don't they have the right to a home? Of course they do.

Some regular travelers take their own belongings: like bed sheets, pillowcases and family

photos to make them feel like home no matter where they are; some stay for long periods in the

same hotel and as a result become very familiar with service and attendants; others may simply

put some flowers by the hotel window to make things more homely. __2__!

And how about maintaining relationships while in transit? __3__; some send letters and

postcards, or even photos; others may just call and say hi, just to let their friends know that they're

高考英语改错专练14篇-含答案

高考英语改错专练14篇-含答案(总10页)

--本页仅作为文档封面,使用时请直接删除即可--

--内页可以根据需求调整合适字体及大小-- 短文改错专练(一)

假定英语课上老师要求同桌之间交换修改作文,请你修改你同桌写的以下作文。文中共有10处语言错误,每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

增加:在缺词处加一个漏字符号(∧),并在其下面写出该加的词。

删除:把多余的词用斜线(\)划掉。

修改:在错的词下划一横线,并在该词下面写出修改后的词。

注意:1. 每处错误及其修改均仅限一词;

2. 只允许修改10处,多者(从第11处起)不计分。

A

My mom and I were out driving when we saw a car ahead of us slow down

sudden and then came to stop as it reached the side of the road. We pulled

over and asking the woman inside the car if she needed any helps. She said “Yes,

please!” Since we were right next by a parking lot, we tried to push her car into it.

We weren’t very successful, as it is a heavy car. Then a man and his kids came

over and offered his help as well as! Together we got the woman’s car into the

parking lot, which she was safe and could get the help she needed. We both

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