已知直线 y=kx+3(k&0)分别交 x轴、y 轴于A、B两点，线段 OA 上有一动点P由原点O向点A运动，速度为每秒1个单位长度，过点P作x轴的垂线交直线AB于点C，设运动时间为t秒.
(1)当 k=-1时，线段OA上另有一动点Q 由点A 向点O运动，它与点 P 以相同速度同时出发，当点P到达点A时两点同时停止运动(如图 1).
①直接写出 t=1秒时 C、Q两点的坐标；
②若以Q、C、A为顶点的三角形与△AOB 相似，求t的值.
(2)当时，设以C为顶点的抛物线y=+n与直线AB的另一交点为D(如图 2).
①求CD的长；
②设△COD的OC边上的高为 h，当 t为何值时h的值最大？
解：(1)①C(1，2)，Q(2，0).
②由题意得：P（t，0），C（t，-t+3），Q（3-t，0）分两种情形讨论：情形一：当△AQC∽△AOB时，AQC =AOB= 90°，∴ CQ⊥OA，∵CP⊥OA，∴点P与点Q重合，OQ=OP，即3-t= t，∴t=1.5；情形二：当△ACQ∽△AOB时，ACQ=AOB=90°，∵OA = OB = 3，∴△AOB是等腰直角三角形，∴△ACQ是等腰直角三角形，∵CP⊥OA，∴AQ= 2CP，即 t = 2(-t +3)，∴t = 2，∴满足条件的t的值是1.5秒或2秒；(2)①由题意得：C(t，-t+ 3)∴以C为顶点的抛物线解析式是y= ，由=-x+3，解得：；过点D作DE⊥CP于点E，则DEC= AOB =90°，DE// OA，∴EDC=OAB，∴△DEC∽△AOB，∴，∵AO= 4，AB = 5，DE=t-∴CD= ②∵CD=，CD边上的高= ，∴，∴为定值；要使OC边上的高h的值最大，只要OC最短因为当OC⊥AB时OC最短，此时OC的长为，BCO=90°，∵AOB=90°，∴COP=90°-BOC=OBA，又∵CP⊥OA，∴∴，OP=，即t=，∴当t为秒时，h的值最大。
阅读理解。
Some people believe that schools will no longer be necessary in the near future. They say that because of the Internet and other technology,there is no longer any need for school building.classes or teachers. Perhaps this will be true one day,but if the world didn"t have schools,I can"t imagine(想象) how our society will be. In fact,we should learn how to use new technology to make school better.We should invent a new kind of school that is linked (连接 ) to
libraries , museums , science
centers ,labs and even companies. Technological companies should create learning programs for schools. Scientists could give talks through the Internet. TV networks and local stations could develop programs about things that students are studying in schools. Labs could be set up on websites to show new technology so students can see it on the Internet.Is this a dream? No. There are already many cities where this is beginning to happen. Here the whole city is linked to the Internet,and learning can take place at home ,at school,and in the office. Businesses provide programs for the schools and society. The schools provide computer labs for people without computers at home. Because everyone can go on the Internet,older people use it as much as younger ones,and everyone can visit faraway libraries and museums as easily as nearby ones. How will this new kind of school change the usual way of learning? It is too early to be sure,but it is very exciting to think about it.Technologvand we will all learn something from the Internet.
1. Who thinks that students don"t need to learn at school?
A.Everyone.
B.The writer.
C.Some people.
D.The teachers.
2.What does“a new kind of school”mean in this passage?
A.A school with few new teachers.
B.A schoo1 with many new students.
C.A schoo1 with many new computers.
D.A schoo1 which is linked to the Internet.
3.According to the text,older people______．
A.never go on the Internet as younger ones
B.go on the Internet as often as younger ones
C.go to the computer lab to study new things
D.are afraid of the internet and other technology
4.What the writer thinks is that____.
A.schools are still necessary
B.more schools should be built
C.there should be fewer schools
D.more computers are needed in schools
New York, London, Paris and other big cities are exciting places to live in. There are many interesting things to see and to do in big cities. You can go to different kinds of theaters to see plays and films. You can also go shopping to buy things from all over the world.But there are more serious problems in big cities, too. The cost of living is high and there are too many people in big cities. Every year many people move to the cities because there are more chances to find work, to study at good schools and to receive good medical care（医疗）. But sometimes these people can’t find work or a good place to live in. Also too many people in such a small place make it hard to keep the cities safe and clean.Some people enjoy living in big cities, but others don’t. When people move to big cities, they should think about the problems of living there.阅读短文，根据短文内容判断下列句子的正(A)误(B)。小题1:There are many interesting things to see and to do in big cities.小题2:You can enjoy plays and films in different schools.小题3:The cost of living isn’t high and there are too many people in big cities.小题4:People move to the cities because there are more chances to find work, to study at good schools and to receive good medical care.小题5:All people enjoy living in big cities.
阅读理解。
Some people believe that schools will no longer be necessary in the near future. They say that because of the Internet and other new technology, there is no longer any need for school buildings, classes or teachers.Perhaps this will be true one day, but if the world has no schools, I can"t imagine how our society will be. In fact, we should learn how to use new technology to make schools better. We should invent a new kind of school that is linked (连接) to libraries, museums, science centres, labs and even companies. Technological companies should create (创造) learning programs for schools. Scientists could give talks through the Internet. TV networks and local (本地的) stations could develop programs about things students are studying in school. Labs could set up websites to show technology so students could see it on the Internet.
Is this a dream? No. There are already many cities where this is beginning to happen. Here the whole city islinked to the Internet, and learning can take place at home, at school, and in the office. Businesses provide programs for schools and society. The schools provide computer labs for people without their own computersat home. Because everyone can go on the Internet, older people use it as much as younger ones, and everyone can visit faraway libraries and museums easily. How will this new kind of school change the usual way oflearning? It is too early to be sure, but it is very exciting to think about it. Technology will change the way we
schools and we will all learn something from the Internet.
1. Who" thinks that students don"t have to learn at school?
A. Everyone. B. The writer. C. Some people.D. The teachers.
2. What does "a new kind of school" mean in the passage?
A. A school with many new computers. B. A school with many new students. C. A school with many new teachers. D. A school which is linked to the Internet.
3. Older people _____.
A. never go on the Internet B. go on the Internet more often than younger onesC. go on the Internet as often as younger onesD. go on the Internet less often than younger ones
4. The writer thinks that _____.
A. schools are still necessary B. more schools should be built C. there should be fewer schools D. more computers are needed in schools
5. Which of the following sentences is NOT true?
A. Technology will change our way of learning. B.
If you are a student, you can set up websites to show new technology. C. The schools provide computer labs for those who have no personal computers.D. On the Internet, you can visit another city"s library easily.
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根据字母表顺序,重新
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1.B D C W Q ________________ 2.A E I O U&________________ 3.J O Q P Y&________________ 4.C T H J K&________________ 5.V Y T I W&________________
1.B C D Q&W& 2.A E I O U &3.J O P Q Y& 4.C H J K T &5.I T V W Y1?0?0?6?2?6 K?B?S ?????????(E?1?3?3?0)-2?0?1?0 F?I?F?A ????? ????? ?_土豆_高清视频在线观看1、m,s,n,o,w,n,a 2、s,n,a,e,s,o ,能组成词并翻译1、m,s,n,o,w,n,a 2、s,n,a,e,s,o 3、c,u,e.b.e.a.s 4、e,t.b,s 5、i,s,n,g,p,r 6、c,w.h,h,i 7、o,w,k,r,能组成词并翻译_百度作业帮
1、m,s,n,o,w,n,a 2、s,n,a,e,s,o ,能组成词并翻译1、m,s,n,o,w,n,a 2、s,n,a,e,s,o 3、c,u,e.b.e.a.s 4、e,t.b,s 5、i,s,n,g,p,r 6、c,w.h,h,i 7、o,w,k,r,能组成词并翻译
1、m,s,n,o,w,n,a 2、s,n,a,e,s,o ,能组成词并翻译1、m,s,n,o,w,n,a 2、s,n,a,e,s,o 3、c,u,e.b.e.a.s 4、e,t.b,s 5、i,s,n,g,p,r 6、c,w.h,h,i 7、o,w,k,r,能组成词并翻译
1.snowman 雪人2.season 季节3.because 因为4.best 最好的5.spring 春天,泉6.which 哪一个7.work 工作翻译只是取了最常用的意义已知直线y=kx-6（k＞0）分别交x轴、y轴于A、B两点，线段OA上有一动点P由原点O向点A运动，速度为每秒1个单位长度，过点P作x轴的垂线交直线AB于点C，设运动时间为t秒．（1）填空：点P的坐标为（____，____）；（2）当k=1时，线段OA上另有一动点Q由点A向点O运动，它与点P以相同速度同时出发，当点P到达点A时两点同时停止运动，如图①．作BF⊥PC于点F，若以B、F、Q、P为顶点的四边形是平行四边形，求t的值．（3）当k=3/4时，设以C为顶点的抛物线y=（x+m）2+n与直线AB的另一交点为D（如图②），设△COD的OC边上的高为h，问：是否存在某个时刻t，使得h有最大值？若存在，试求出t的值；若不存在，请说明理由．-乐乐课堂
& 二次函数综合题知识点 & “已知直线y=kx-6（k＞0）分别交x轴...”习题详情
102位同学学习过此题，做题成功率63.7%
已知直线y=kx-6（k＞0）分别交x轴、y轴于A、B两点，线段OA上有一动点P由原点O向点A运动，速度为每秒1个单位长度，过点P作x轴的垂线交直线AB于点C，设运动时间为t秒．（1）填空：点P的坐标为（t&，0&）；（2）当k=1时，线段OA上另有一动点Q由点A向点O运动，它与点P以相同速度同时出发，当点P到达点A时两点同时停止运动，如图①．作BF⊥PC于点F，若以B、F、Q、P为顶点的四边形是平行四边形，求t的值．（3）当k=34时，设以C为顶点的抛物线y=（x+m）2+n与直线AB的另一交点为D（如图②），设△COD的OC边上的高为h，问：是否存在某个时刻t，使得h有最大值？若存在，试求出t的值；若不存在，请说明理由．
本题难度：较难
题型：填空题&|&来源：2012-晋江市质检
分析与解答
习题“已知直线y=kx-6（k＞0）分别交x轴、y轴于A、B两点，线段OA上有一动点P由原点O向点A运动，速度为每秒1个单位长度，过点P作x轴的垂线交直线AB于点C，设运动时间为t秒．（1）填空：点P的坐标为（___...”的分析与解答如下所示：
（1）根据P点的运动速度和运动时间可得到OP的长，则P点坐标可求．（2）从图中可以看出，已知的条件有PQ∥BF，只需令PQ=BF就能得到以B、F、P、Q为顶点的四边形是平行四边形的结论，在求PQ的表达式时要注意P、Q的位置．（3）首先要求出A、B、C、D四点的坐标，过D作PC的垂线交PC于E，根据D点坐标和抛物线对称轴方程，可确定E点坐标及DE的长，根据构建的相似三角形△CED、△BOA求出CD的长，此时能发现CD长为定值，而△OCD中CD边上的高也是定值（可在△OAB中利用面积公式求得），所以OC边越短、OC边上的高h就越大，因此当h最大时，OC应垂直CD，即OC是CD边的高，根据前面求得的OC长，结合相似三角形△OPC、△BOA求出OP的长，即可求得t的值．
解：（1）由题意，动点P的速度为每秒1个单位长度，运动时间为t秒，则OP=t，即：P（t，0）（2）当k=1时，直线AN的解析式为：y=x-6，令y=0，则x=6，则AO=6由题意得：PF∥OB，BF∥OP，∠AOB=90°，∴四边形BFPO是矩形，∴BF=OP=t，∴AQ=OP=t，PQ=6-2t若四边形BFQP是平行四边形，如图1，则BF=PQ，t=6-2t，解得：t=2，符合题意；若四边形BFPQ是平行四边形，如图2，则BF=PQ，t=2t-6，即点P与点A重合时，此时四边形BFPQ是矩形，故t=6符合题意．（3）由题意得：C（t，34t-6），以C为顶点的抛物线解析式是y=（x-t）2+34t-6；当k=34时，直线AB解析式为：y=34x-6，同理可得：A（8，0），B（0，-6）．由（x-t）2+34t-6=34x-6，得解：x1=t，x2=t+34如图3，过点D作DE⊥CP于点E，则∠DEC=∠AOB=90°．∵PC∥OB，∴∠OBA=∠ECD，∴△DEC∽△AOB∴DEOA=CDBA在Rt△AOB中，由勾股定理得：AB=√OA2+OB2=√82+62=10．∵AO=8，AB=10，DE=（t+34）-t=34，∴CD=DEoBAOA=34×108=1516．∴CD边上的高=6×810=245，∵∠AOB=90°，∴∠COP=90°-∠BOC=∠OBA．又∵CP⊥OA，即∠OPC=90°，∴∠OPC=∠AOB=90°∴Rt△OPC∽Rt△BOA∴OPBO=OCBA，即OP=OCoBOBA=245×610=7225∴当t=7225时，h的值最大．
该题是图形中的动点问题，考查了二次函数、相似三角形、图形面积的求法、特殊四边形的判定和性质等重要知识；（3）的难度较大，能否找出h最大时OC的位置和大小是解答题目的关键所在．
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已知直线y=kx-6（k＞0）分别交x轴、y轴于A、B两点，线段OA上有一动点P由原点O向点A运动，速度为每秒1个单位长度，过点P作x轴的垂线交直线AB于点C，设运动时间为t秒．（1）填空：点P的坐标...
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经过分析，习题“已知直线y=kx-6（k＞0）分别交x轴、y轴于A、B两点，线段OA上有一动点P由原点O向点A运动，速度为每秒1个单位长度，过点P作x轴的垂线交直线AB于点C，设运动时间为t秒．（1）填空：点P的坐标为（___...”主要考察你对“二次函数综合题”
等考点的理解。
因为篇幅有限，只列出部分考点，详细请访问。
二次函数综合题
（1）二次函数图象与其他函数图象相结合问题解决此类问题时，先根据给定的函数或函数图象判断出系数的符号，然后判断新的函数关系式中系数的符号，再根据系数与图象的位置关系判断出图象特征，则符合所有特征的图象即为正确选项．（2）二次函数与方程、几何知识的综合应用将函数知识与方程、几何知识有机地结合在一起．这类试题一般难度较大．解这类问题关键是善于将函数问题转化为方程问题，善于利用几何图形的有关性质、定理和二次函数的知识，并注意挖掘题目中的一些隐含条件．（3）二次函数在实际生活中的应用题从实际问题中分析变量之间的关系，建立二次函数模型．关键在于观察、分析、创建，建立直角坐标系下的二次函数图象，然后数形结合解决问题，需要我们注意的是自变量及函数的取值范围要使实际问题有意义．
与“已知直线y=kx-6（k＞0）分别交x轴、y轴于A、B两点，线段OA上有一动点P由原点O向点A运动，速度为每秒1个单位长度，过点P作x轴的垂线交直线AB于点C，设运动时间为t秒．（1）填空：点P的坐标为（___...”相似的题目：
[2002o广州o模拟]直线y=x与抛物线y=x2-2的两个交点的坐标分别是（　　）（2，2），（1，1）（2，2），（-1，-1）（-2，-2），（1，1）（-2，-2），（-l，-1）
[2015o乐乐课堂o练习]直线y=x+2与抛物线y=x2+2x的交点坐标是（　　）（1，3）（-2，0）（1，3）或（-2，0）以上都不是
[2015o乐乐课堂o练习]直线y=2x-1与抛物线y=x2的交点坐标是（　　）（0，0），（1，1）（1，1）（0，1），（1，0）（0，-1），（-1，0）
“已知直线y=kx-6（k＞0）分别交x轴...”的最新评论
该知识点好题
1（2013o淄博）如图，Rt△OAB的顶点A（-2，4）在抛物线y=ax2上，将Rt△OAB绕点O顺时针旋转90°，得到△OCD，边CD与该抛物线交于点P，则点P的坐标为（　　）
2二次函数y=x2-8x+15的图象与x轴相交于M，N两点，点P在该函数的图象上运动，能使△PMN的面积等于12的点P共有（　　）
3如图，半圆A和半圆B均与y轴相切于O，其直径CD，EF均和x轴垂直，以O为顶点的两条抛物线分别经过点C，E和点D，F，则图中阴影部分面积是（　　）
该知识点易错题
1（2012o南浔区二模）如图，点A（a，b）是抛物线y=12x2上一动点，OB⊥OA交抛物线于点B（c，d）．当点A在抛物线上运动的过程中（点A不与坐标原点O重合），以下结论：①ac为定值；②ac=-bd；③△AOB的面积为定值；④直线AB必过一定点．正确的有（　　）
2（2012o静海县二模）如图，抛物线m：y=ax2+b（a＜0，b＞0）与x轴于点A、B（点A在点B的左侧），与y轴交于点C．将抛物线m绕点B旋转180°，得到新的抛物线n，它的顶点为C1，与x轴的另一个交点为A1．若四边形AC1A1C为矩形，则a，b应满足的关系式为（　　）
3如图，已知抛物线P：y=ax2+bx+c（a≠0）与x轴交于A、B两点（点A在x轴的正半轴上），与y轴交于点C，矩形DEFG的一条边DE在线段AB上，顶点F、G分别在线段BC、AC上，抛物线P上部分点的横坐标对应的纵坐标如下：
x&…&-3&-2&1&2&…&y&…&-52&-4&-52&0&…&（1）求A、B、C三点的坐标；（2）若点D的坐标为（m，0），矩形DEFG的面积为S，求S与m的函数关系，并指出m的取值范围．
欢迎来到乐乐题库，查看习题“已知直线y=kx-6（k＞0）分别交x轴、y轴于A、B两点，线段OA上有一动点P由原点O向点A运动，速度为每秒1个单位长度，过点P作x轴的垂线交直线AB于点C，设运动时间为t秒．（1）填空：点P的坐标为（____，____）；（2）当k=1时，线段OA上另有一动点Q由点A向点O运动，它与点P以相同速度同时出发，当点P到达点A时两点同时停止运动，如图①．作BF⊥PC于点F，若以B、F、Q、P为顶点的四边形是平行四边形，求t的值．（3）当k=3/4时，设以C为顶点的抛物线y=（x+m）2+n与直线AB的另一交点为D（如图②），设△COD的OC边上的高为h，问：是否存在某个时刻t，使得h有最大值？若存在，试求出t的值；若不存在，请说明理由．”的答案、考点梳理，并查找与习题“已知直线y=kx-6（k＞0）分别交x轴、y轴于A、B两点，线段OA上有一动点P由原点O向点A运动，速度为每秒1个单位长度，过点P作x轴的垂线交直线AB于点C，设运动时间为t秒．（1）填空：点P的坐标为（____，____）；（2）当k=1时，线段OA上另有一动点Q由点A向点O运动，它与点P以相同速度同时出发，当点P到达点A时两点同时停止运动，如图①．作BF⊥PC于点F，若以B、F、Q、P为顶点的四边形是平行四边形，求t的值．（3）当k=3/4时，设以C为顶点的抛物线y=（x+m）2+n与直线AB的另一交点为D（如图②），设△COD的OC边上的高为h，问：是否存在某个时刻t，使得h有最大值？若存在，试求出t的值；若不存在，请说明理由．”相似的习题。