(1)将点(1,b)代入2个函数式得a=b=-1
(2)将a=1代入函数式得Y=-X²
当X=0时Y=0,顶点是(0,0),对成轴是Y轴
(3)当Y=-2时X²=2,则X=√2,△面积=2√2*2/2=2√2.