limi627
幼苗
共回答了23个问题采纳率：87% 举报
x^2-y^2=m
y=x/2
代入
x^2-x^2/4=m
3x^2-4m=0
x1+x2=0,x1*x2=-4m/3
(x1-x2)^2=(x1+x2)^2-4x1x2=16m/3
AB在y=x/2上
所以(y1-y2)^2=(x1/2-x2/2)^2=(x1-x2)^2/4=4m/3
AB^2=(x1-x2)^2+(y1-y2)^2=16m/3+4m/3=20m/3=(4根号15)^2=240
m=36
x^2/36-y^2/36=1
1年前
6
赞
