對(duì)于一個(gè)函數(shù),如果存在實(shí)數(shù)m,使得當(dāng)函數(shù)的自變量為m時(shí),函數(shù)值也是m,我們稱該函數(shù)為智能函數(shù),點(diǎn)(m,m)為智能函數(shù)上的智能點(diǎn).
(1)判斷函數(shù)y=2x-3是否為智能函數(shù);
(2)二次函數(shù)y=ax
2+bx+c與x軸交于A(x
1,0),B(x
2,0)兩點(diǎn),且
,若無(wú)論b為何值,該函數(shù)都是智能函數(shù),求a的取值范圍;
(3)在第(2)問(wèn)的前提下,若C、D為函數(shù)y=ax
2+bx+c上的智能點(diǎn),且C、D關(guān)于直線
對(duì)稱,求b的最小值.