设椭圆x^2/a^2+y^2/b^2=1(a>b>0)的左右焦点分别为F1,F2.点P(a,b)满足PF2=F1F2.

问题描述:

设椭圆x^2/a^2+y^2/b^2=1(a>b>0)的左右焦点分别为F1,F2.点P(a,b)满足PF2=F1F2.
(1)求椭圆的离心率e;
(2)设直线PF2与椭圆相交于A,B两点,若直线PF2与圆(x+1)^2+(y-根号3)^2=16相交于M,N两点,且MN=(5/8)AB,求椭圆的方程.