A:,
B:,
C:,
D:,
定义在R上的奇函数fx,f5=0,且对任意不等的正实数x1,x2,都满足fx1-fx2x2-x1<0,则不等式x·f-x>0的解集为( ).
— _________ book?
— The one on your desk.
— It's Tom's
圆x2a2+y2b2=1a>b>0的左、右顶点分别是A,B,左、右焦点分别是F1,F2若AF1,F1F2,F1B成等比数列,则此椭圆的离心率为 ( )