摘要：如图.二次函数y＝ax2+bx+c(a＞0)与坐标轴交于点A.B.C且OA＝1.OB＝OC＝3 ． (1)求此二次函数的解析式． (2)写出顶点坐标和对称轴方程． (3)点M.N在y＝ax2+bx+c的图像上.且MN∥x轴.求以MN为直径且与x轴相切的圆的半径． (1)依题意分别代入 1分 解方程组得所求解析式为······································································ 4分 (2)··············································································· 5分 顶点坐标.对称轴················································································· 7分 (3)设圆半径为.当在轴下方时.点坐标为····························· 8分 把点代入得································································· 9分 同理可得另一种情形 圆的半径为或 10分

网址：http://m.1010jiajiao.com/timu_id_4223704[举报]