解:整理得x^2-a^2y^2=a^2 y=x-1(1)二者有2个不同的交点A,B,解方程得:x^2-a^2(x-1)^2=a^2,x^2-a^2(x^2-2x+1)=a^2,(1-a^2)x^2+2a^2x-2a^2=0,△=4a^4+8a^2(1-a^2), =4a^4+8a^2-8a^4 =8a^2-4a^4>0故2a^2-a^4>0 a^2<2 c=√(a^2+1)e=c/a=√(a^2+1)/a=√(1+1/a^2)所以 1