双曲线y^2/9-x^2/27=1a^2=9,b^2=27.c^2=9+27=36a=3,c=6e=c/a=2椭圆的离心率与双曲线的离心率互为倒数,则有椭圆的离心率是e=1/2x^2/a+y^2/(a-1)=1a'^2=a,b'^2=a-1e^2=c^2/a'^2=(a'^2-b'^2)/a'^2=1-b^2/a'^2=1-(a'-1)/...