【简答题】已知点A(-2,0),B(1,0),平面内的动点P满足|PA|=λ|PB|(λ为常数,λ>0). (1)求点P的轨迹E的方程,并指出其表示的曲线的形状. (2)当λ=2时,P的轨迹E与x轴交于C、D两点,M是轨迹上异于C、D的任意一点,直线l:x=-3,直线CM与直线l交于点C′,直线DM与直线l交于点D'.求证:以C′D′为直径的圆总过定点,并求出定点坐标.
【单选题】变压器的呼吸器又称吸湿器,通常由一根管道和玻璃容器组成,内装( )
【多选题】(多选题)在航空公司柜台工作人员前领队应做的工作是( )。
【单选题】听力原文:M: I can't stand living in this place any more. W: Well, why don't you move then? Q: What does the woman suggest the man to do? (5)
【单选题】听力原文:M: I don't think we can find a better restaurant around here at this time. W: Let's walk a little further to see if there is another one. I just can't bear the noise here. Q: What will the speake...
A.
Look for a better restaurant.
B.
Go to another restaurant by bus.
C.
Take a walk around the city.
D.
Try to find a quiet place.
【单选题】′′a,b是异面直线′′是指1a b= ,且a不平行于b;2a ⊂ 平面α,b ⊂ 平面β,且a b= 3a ⊂ 平面α,b¢平面α 4不存在平面α,能使a ⊂ α,且b ⊂ α成立
【单选题】I don't have ______ time as you do to stand around and talk.
【简答题】化验室蒸馏低沸点易燃液体时,应采用密闭时电热管的()或红外线灯加热;尽量避免用()加热。
【单选题】变压器的呼吸器又称吸湿器,通常由一根管道和玻璃容器组成,内装( )