y=(m-1)x^2+m^2-1的图像经过(0,3):
3=0+m^2-1
抛物线开口向下:
m-1<0
m^2=4且m<1
m=-2
y=(-2-1)x^2+(-2)^2-1 = -3x^2+3=-3(x+1)(x-1)
x1=-1,x2=1
x2-x1=1-(-1)=2
抛物线与x轴的两交点的距离2
y=(m-1)x^2+m^2-1的图像经过(0,3):
3=0+m^2-1
抛物线开口向下:
m-1<0
m^2=4且m<1
m=-2
y=(-2-1)x^2+(-2)^2-1 = -3x^2+3=-3(x+1)(x-1)
x1=-1,x2=1
x2-x1=1-(-1)=2
抛物线与x轴的两交点的距离2