定義:將函數(shù)C的圖象繞點(diǎn)P(0,n)旋轉(zhuǎn)180°,得到新的函數(shù)C
1的圖象,我們稱函數(shù)C
1是函數(shù)C關(guān)于點(diǎn)P的相關(guān)函數(shù).
例如:當(dāng)n=1時(shí),函數(shù)y=
(x-6)
2+3關(guān)于點(diǎn)P(0,1)的相關(guān)函數(shù)為y=
(x+6)
2-1.
(1)當(dāng)n=0時(shí),
①二次函數(shù)y=x
2關(guān)于點(diǎn)P的相關(guān)函數(shù)為
y=-x2
y=-x2
;
②點(diǎn)A(2,3)在二次函數(shù)y=ax
2-2ax+a(a≠0)關(guān)于點(diǎn)P的相關(guān)函數(shù)的圖象上,求a的值;
(2)函數(shù)y=-x
2+
關(guān)于點(diǎn)P的相關(guān)函數(shù)是y=x
2,則n=
;
(3)當(dāng)
n-1≤x≤
n+3時(shí),函數(shù)y=-2x
2+nx
n
2的相關(guān)函數(shù)的最小值為7,求n的值.