x | … | -3 | -2 | -1 | 0 | 1 | 2 | 3 | … |
y=x2 | … | 9 | 4 | 1 | 0 | 1 | 4 | 9 | … |
![](http://www.tongzhuo100.com/uploads/2015/01/20150112114619374.jpg)
![](http://www.tongzhuo100.com/uploads/2015/01/20150112114649673.jpg)
x | … | -4 | -3 | -2 | -1 | 0 | 1 | 2 | 3 | 4 | … |
y=![]() |
… | 8 | 4.5 | 2 | 0.5 | 0 | 0.5 | 2 | 4.5 | 8 | … |
x | … | -2 | -1.5 | -1 | -0.5 | 0 | 0.5 | 1 | 1.5 | 2 | … |
y=2x2 | … | 8 | 4.5 | 2 | 0.5 | 0 | 0.5 | 2 | 4.5 | 8 | … |
![](http://www.tongzhuo100.com/uploads/2015/01/20150112115310884.jpg)
![](http://www.tongzhuo100.com/uploads/2015/01/20150112114836691.jpg)
![](http://www.tongzhuo100.com/uploads/2015/01/20150112114813501.jpg)
![](http://www.tongzhuo100.com/uploads/2015/01/20150112115104003.jpg)
a>0 | a<0 | |
开口方向 | 向上 | 向下 |
对称轴 | y轴 | y轴 |
顶点 | (0,0)最低点 | (0,0)最高点 |
增减性 | 当x<0时,y随x的增大而减小 当x>0时,y随x的增大而增大 |
当x<0时,y随x的增大而增大 当x>0时,y随x的增大而减小 |
开口大小 | |a|越大,开口越小 |
![](https://www.tongzhuo100.com/upload/icon/cc6673863f61d2da92e5116624542b5b.jpg)
张老师
女,中教高级职称
优秀教师,市级骨干教师、“教学标兵”、劳动模范,市数学教学与研究科研组带头人,注重教学改革与实践。