设P(x,y),[PF]/[x-8]=1/2 4[PF]^2=(x-8)^2
4(x-2)^2+4y^2=(x-8)^2
4x^2-16x+16+4y^2=x^2-16x+64
3x^2+4y^2=48
x^2/16+y^2/12=1
点P的轨迹是椭圆,方程式为:x^2/16+y^2/12=1
设P(x,y),[PF]/[x-8]=1/2 4[PF]^2=(x-8)^2
4(x-2)^2+4y^2=(x-8)^2
4x^2-16x+16+4y^2=x^2-16x+64
3x^2+4y^2=48
x^2/16+y^2/12=1
点P的轨迹是椭圆,方程式为:x^2/16+y^2/12=1