两点A(-3,0)与B(3,0),若PA-PB=2,则根据双曲线的定义得,点P的轨迹方程为双曲线的右支.
PA-PB=2a=2, a=1
F1F2=AB=2c=6, c=3
c^2=a^2+b^2
b^2=9-1=8
焦点在X轴上,则P方程是x^2/1-y^2/8=1.(x>=1)