题目内容
(本小题满分5分)已知直线
![](http://thumb.1010pic.com/pic1/imagenew2/czsx/12/90732.gif)
![](http://thumb.1010pic.com/pic1/imagenew2/czsx/13/90733.gif)
(1)求k的值;
(2)求A、B两点的坐标;
(3)过点M作直线MP与y轴交于点P,且△MPB的面积为2,求点P的坐标.
解:(1)∵直线y=kx-3过点M(2,1)
∴
,∴
---------------------------------------------- 1分
(2)∵
,∴![](http://thumb.1010pic.com/pic1/imagenew2/czsx/17/90737.gif)
∴A(
,0),B(0,-3)----------------------------------------- 3分
(3)∵P、B两点在y轴上,
∴点M到y轴的距离为2
∵△MPB的面积为2,∴PB="2 " --------------------------------- 4分
∵B(0,-3)∴点P的坐标为:
,
----------- 5分解析:
略
∴
![](http://thumb.1010pic.com/pic1/imagenew2/czsx/14/90734.gif)
![](http://thumb.1010pic.com/pic1/imagenew2/czsx/15/90735.gif)
(2)∵
![](http://thumb.1010pic.com/pic1/imagenew2/czsx/15/90735.gif)
![](http://thumb.1010pic.com/pic1/imagenew2/czsx/17/90737.gif)
∴A(
![](http://thumb.1010pic.com/pic1/imagenew2/czsx/18/90738.gif)
(3)∵P、B两点在y轴上,
∴点M到y轴的距离为2
∵△MPB的面积为2,∴PB="2 " --------------------------------- 4分
∵B(0,-3)∴点P的坐标为:
![](http://thumb.1010pic.com/pic1/imagenew2/czsx/19/90739.gif)
![](http://thumb.1010pic.com/pic1/imagenew2/czsx/0/90740.gif)
略
![](http://thumb2018.1010pic.com/images/loading.gif)
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