∴該函數(shù)的圖象開口方向向下.
又∵二次函數(shù)的圖象與x軸交于A(-2,0),B(3,0)兩點(diǎn),
∴該拋物線的對(duì)稱軸是x=
-2+3 |
2 |
1 |
2 |
∴該函數(shù)的頂點(diǎn)是(
1 |
2 |
∴可設(shè)該二次函數(shù)解析式為y=a(x-
1 |
2 |
則將點(diǎn)A的坐標(biāo)代入,得0=a(-2-
1 |
2 |
8 |
25 |
∴二次函數(shù)的函數(shù)關(guān)系式y(tǒng)=-
8 |
25 |
1 |
2 |
(2)由(1)知,頂點(diǎn)P的坐標(biāo)是(
1 |
2 |
由A(-2,0),B(3,0)知AB=5,
則S△ABP=
1 |
2 |