【单选题】In terms of pressure and temperature in the refrigerant in the compressor, what happens to the primary? .
A.
its pressure and temperature are both lowered
B.
its pressure and temperature are both raised
C.
its pressure is lowered and its temperature is raised
D.
its pressure is raised and its temperature is lowered
【判断题】街道派出所的人民警察是我国武装力量。判断对错
【简答题】已知点A,D分别是椭圆 (a>b>0)的左顶点和上顶点,点P是线段AD上的任意一点,点F 1 ,F 2 分别是椭圆的左、右焦点,且 的最大值是1,最小值是 , (Ⅰ)求椭圆C的方程; (Ⅱ)设椭圆的右顶点为B,点S是椭圆上位于x轴上方的动点,直线AS,BS与直线L:x= 分别交于M,N两点,求线段MN长度的最小值; (Ⅲ)当线段MN的长度最小时,在椭圆上是否存在T点,使得△TSB的面积是 ?若存在...
【简答题】已知椭圆C的中心在坐标原点,长轴在x轴上,F 1 、F 2 分别为其左、右焦点,P在椭圆上任意一点,且 F 1 P ? F 2 P 的最大值为1,最小值为-2. (1)求椭圆C的方程; (2)设A为椭圆C的右顶点,直线l是与椭圆交于M、N两点的任意一条直线,若AM⊥AN,证明直线l过定点.