拋物線y=4x2-1與y軸的交點(diǎn)坐標(biāo)是 ,與x軸的交點(diǎn)坐標(biāo)是 .
【答案】
分析:令y=0,可求拋物線與x軸的交點(diǎn)坐標(biāo);令x=0,可求拋物線與y軸的交點(diǎn)坐標(biāo).
解答:解:當(dāng)x=0時(shí),y=-1,即與y軸的交點(diǎn)坐標(biāo)是(0,-1);
當(dāng)y=0時(shí),x=±
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131211103157661537792/SYS201312111031576615377001_DA/0.png)
,所以與x軸的交點(diǎn)坐標(biāo)是(-
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131211103157661537792/SYS201312111031576615377001_DA/1.png)
,0)和(
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131211103157661537792/SYS201312111031576615377001_DA/2.png)
,0).
點(diǎn)評:主要考查了二次函數(shù)圖象與(x軸)y軸的交點(diǎn)坐標(biāo)特點(diǎn):(x軸)y軸上的點(diǎn)的(縱坐標(biāo))橫坐標(biāo)為0.求此類問題可令函數(shù)的(y=0)x=0,求出(x值)y值即是與y軸的交點(diǎn)(橫坐標(biāo))縱坐標(biāo).