椭圆 x 2 a 2 + y 2 b 2 =1(a>b>0) 人两个焦点为F 1 (-c,0)、F 2 (c,0),M是椭圆上一点,且满足 F 1 M ? F 2 M =0 . (1)求离心率e人取值范围; (2)当离心率e取得最小值时,点N(0,9)到椭圆上人点人最远距离为 5 2 ,求此时椭圆人方程.
【简答题】I 、从方框中选择正确的词,并用其适当形式填空 best, think, work, interest, subject 1.--Where are Tom and Jim? --They are on math problems in the classroom. 2.--What do you teach? --I teach English. 3.--What do you of our c...