Question

方已知△ABC的周長是8,B、C的坐標分別是(-1,0)和(1,0),則頂點A的軌跡方程是(    )

A.=1(x≠±3)                         B.=1(x≠0)

C.=1(y≠0)                           D.=1(y≠0)

Answer 1

A

解析:

由題意得|AB|+|AC|=6,∴A點軌跡為以B、C為兩焦點,長軸長為6的橢圓.

又∵c=1,a=3,∴b²=8.∴+=1(x≠±3)為所求.