题目

Twenty students want to attend the class that aims to teach to read first. A . what B . who C . how D . why 答案：C如图，双曲线的两顶点为A1，A2，虚轴两端点为，，两焦点为F1，F2。若以A1A2为直径的圆内切于菱形F1B1F2B2，切点分别为A，B，C，D。则 （Ⅰ）双曲线的离心率e=______； （Ⅱ）菱形F1B1F2B2的面积S1与矩形ABCD的面积S2的比值__________。