设:AB中点的坐标为(x0,y0)
x0=(x1+x2)2
y0=(y1+y2)2
x1^2=4y1
x2^2=4y2
y1*y2=-x1*x2 (0A、OB斜率相乘=-1)
五个式子联立得出:y0=4+-x02 (当x大于0时取正,当x小于0时取负)
设:AB中点的坐标为(x0,y0)
x0=(x1+x2)2
y0=(y1+y2)2
x1^2=4y1
x2^2=4y2
y1*y2=-x1*x2 (0A、OB斜率相乘=-1)
五个式子联立得出:y0=4+-x02 (当x大于0时取正,当x小于0时取负)