Read each phrase and decide who could say it - the person who makes the call (the caller), or the person who receives the call (the receiver)? 1. Can I help you?
【简答题】已知F 1 、F 2 分别是椭圆 x 2 a 2 + y 2 b 2 =1(a>0,b>0) 的左、右焦点,其左准线与x轴相交于点N,并且满足, F 1 F 2 =2 N F 1 ,| F 1 F 2 |=2 . (1)求此椭圆的方程; (2)设A、B是这个椭圆上的两点,并且满足 NA =λ NB ,当 λ∈[ 1 5 , 1 3 ] 时,求直线AB的斜率的取值范围.