1 |
3 |
1 |
3 |
(2)當(dāng)m≠0時(shí),∵f(0)=1,∴拋物線過點(diǎn)(0,1).
若m<0時(shí),f(x)的開口向下,如圖所示.
![](http://hiphotos.baidu.com/zhidao/pic/item/4ec2d5628535e5dd656b936d75c6a7efce1b6238.jpg)
二次函數(shù)的兩個(gè)零點(diǎn)必然是一個(gè)在原點(diǎn)右側(cè),一個(gè)在原點(diǎn)左側(cè).
若m>0,f(x)的開口向上,如圖所示,要使函數(shù)的零點(diǎn)在原點(diǎn)右側(cè),當(dāng)且僅當(dāng)△=9-4m≥0,
3m |
2 |
9 |
4 |
![](http://hiphotos.baidu.com/zhidao/pic/item/cf1b9d16fdfaaf5179a4b70d8f5494eef01f7a38.jpg)
綜上所述,m的取值范圍為(-∞,
9 |
4 |