(1)求點(diǎn)B的坐標(biāo);
(2)求過(guò)點(diǎn)A、O、B的拋物線的解析式;
(3)在(2)中拋物線的對(duì)稱軸上是否存在點(diǎn)C,使△AOC的周長(zhǎng)最小?若存在,求出點(diǎn)C的坐標(biāo);若不存在,請(qǐng)說(shuō)明理由.
解析:(1)由面積公式及A點(diǎn)縱坐標(biāo)可求OB,確定B點(diǎn)坐標(biāo);
(2)拋物線過(guò)O(0,0),B(-2,0)兩點(diǎn),設(shè)拋物線交點(diǎn)式y(tǒng)=ax(x+2),將點(diǎn)A(1,根3 )代入求a即可;
(3)存在.根據(jù)拋物線的對(duì)稱性,得出點(diǎn)O關(guān)于對(duì)稱軸的對(duì)稱點(diǎn)為B點(diǎn),連接AB,與對(duì)稱軸的交點(diǎn)C即為所求,根據(jù)A、B兩點(diǎn)坐標(biāo)求直線AB的解析式,由對(duì)稱軸x=-1求C點(diǎn)縱坐標(biāo)
![](http://d.hiphotos.baidu.com/zhidao/wh%3D600%2C800/sign=37998b31e4cd7b89e93932853f146e9f/48540923dd54564e71c66fc2b1de9c82d0584fae.jpg)