8.已知点F,A分别为双曲线C：x²/a²-y²/b²=1(a>0,b>0)的左焦点、右顶点,点B（0,b）满足向量FB·向量AB=0,则双曲线的离心率为A.根号2 B.根号3 C.1+根号3/2 D.1+根号5/2

8.已知点F,A分别为双曲线C：x²/a²-y²/b²=1(a>0,b>0)的左焦点、右顶点,点B（0,b）满足向量FB·向量AB=0,则双曲线的离心率为A.根号2 B.根号3 C.1+根号3/2 D.1+根号5/2
8.已知点F,A分别为双曲线C：x²/a²-y²/b²=1(a>0,b>0)的左焦点、右顶点,点B（0,b）满足向量FB·向量AB=0,则双曲线的离心率为
A.根号2 B.根号3 C.1+根号3/2 D.1+根号5/2

8.已知点F,A分别为双曲线C：x²/a²-y²/b²=1(a>0,b>0)的左焦点、右顶点,点B（0,b）满足向量FB·向量AB=0,则双曲线的离心率为A.根号2 B.根号3 C.1+根号3/2 D.1+根号5/2
F坐标是(-c,0),A(a,0)
FB=(c,b),AB=(-a,b)
FB*AB=-ac+b^2=0
b^2=c^2-a^2
c^2-ac-a^2=0
e^2-e-1=0
e=(1+根号5)/2
选择D

斜边是斜边上中线的两倍 列出abc的关系式