解：將點(diǎn)?$A(-1，$??$3)$?代入?$y=ax^2$?得?$3=a×(-1)^2$?
∴?$a=3，$?即?$y=3x^2$?
?$(1)$?這個(gè)二次函數(shù)的開口向上，對(duì)稱軸為?$y$?軸
?$(2)a＞0，$?則函數(shù)?$y$?有最小值，為?$0，$?此時(shí)對(duì)應(yīng)的?$x$?值為?$0$?
?$(3)$?點(diǎn)?$A$?關(guān)于?$y$?軸的對(duì)稱點(diǎn)為?$B(1，$??$3)$?
令?$x=1，$??$y=3×1^2=3$?
∴點(diǎn)?$B$?在函數(shù)圖像上
