Relatives of the emperor should also be punished according to the law if they commit a c____.
已知双曲线x2a2﹣y2b2=1(a,b>0)的左、右焦点分别为F1F2,P为左支上一点,P到左准线的距离为d,若d、|PF1|、|PF2|成等比数列,则其离心率的取值范围是( )
运载火箭.
分解因式:x2﹣1=____ .
亚洲大陆地理中心位于( )