换一种思路：焦点坐标(0,1),准线方程 y=-1直线方程：y=x+1 → x=y-1代入x^2=4y → (y-1)^2=4y → y^2-6y+1=0,解得 y=3±2√2,由抛物线定义,抛物线上任一点到焦点和到准线距离相等|AF|=3+2√2+1=4+2√2,|FB|=3-2√2+1...