题目内容
P1(2,-1),P2(0,5),且P在P1P2的延长线上,使|![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101221142267870078/SYS201311012211422678700002_ST/0.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101221142267870078/SYS201311012211422678700002_ST/1.png)
A.(2,11)
B.(
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101221142267870078/SYS201311012211422678700002_ST/2.png)
C.(
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101221142267870078/SYS201311012211422678700002_ST/3.png)
D.(2,-7)
【答案】分析:根据P在P1P2的延长线上,由
、
共线可得答案.
解答:解:由题意知P1P2=P2P,
设P(x,y),则(-2,6)=(x,y-5),
∴
,∴
,
∴点P的坐标为(-2,11).
故选A.
点评:本题主要考查向量的共线问题.
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101221142267870078/SYS201311012211422678700002_DA/0.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101221142267870078/SYS201311012211422678700002_DA/1.png)
解答:解:由题意知P1P2=P2P,
设P(x,y),则(-2,6)=(x,y-5),
∴
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101221142267870078/SYS201311012211422678700002_DA/2.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101221142267870078/SYS201311012211422678700002_DA/3.png)
∴点P的坐标为(-2,11).
故选A.
点评:本题主要考查向量的共线问题.
![](http://thumb.zyjl.cn/images/loading.gif)
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P1(2,-1),P2(0,5),且P在P1P2的延长线上,使|
|=2|
|,则点P为( )
p1p |
p p2 |
A、(2,11) | ||
B、(
| ||
C、(
| ||
D、(2,-7) |