设P点坐标为(x,y),则A(x,a),B(x,-a)
x^2+2*a^2=4,a=根号[(4-x^2)/2]
A(x,根号[(4-x^2)/2]),B(x,-根号[(4-x^2)/2])
向量PA乘向量PB=(0,a-y)乘(0,-a-y)=y^2-a^2=1
化简得:x^2+2y^2=6
设P点坐标为(x,y),则A(x,a),B(x,-a)
x^2+2*a^2=4,a=根号[(4-x^2)/2]
A(x,根号[(4-x^2)/2]),B(x,-根号[(4-x^2)/2])
向量PA乘向量PB=(0,a-y)乘(0,-a-y)=y^2-a^2=1
化简得:x^2+2y^2=6