Question

已知点M(x,y)到点F1(-3,0)的距离与它到F2(3,0)的距离的差的绝对值是4,求M点的轨迹

Answer 1

由题意可知M点轨迹为双曲线,设为(x/a)^2-(y/b)^2=1

则a=4/2=2,c=3

b^2=c^2-a^2=5

所以M点轨迹方程为(x^2)/4-(y^2)/5=1