(1)短轴一个端点到右焦点的距离为2,a=2,离心率为根号3/2,c=根号3,b=1
x2/4+y2=1
(2)PF1*PF2
=PF1*(2a-PF1)
=PF1*(4-PF1)
=4-(2-PF1)^2
a-c=