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8-7圆锥曲线的综合问题(理)闯关密练特训1.(2012·潍坊教学质量监测)椭圆eq f(x24)eq f(y23)1的离心率为e点(1e)是圆x2y2-4x-4y40的一条弦的中点则此弦所在直线的方程是( )A.3x2y-40 B.4x6y-70C.3x-2y-20 D.4x-6y-10[答案] B[解析] 依题意得eeq f(12)圆心坐标为(22)圆心(22)与点(1
10-1随机抽样基础巩固强化1.问题:①三种不同的容器中分别装有同一型号的零件400个200个150个现在要从这750个零件中抽取一个容量为50的样本②从20名学生中选出3名参加座谈会.方法:Ⅰ.随机抽样法 Ⅱ.系统抽样法 Ⅲ.分层抽样法.其中问题与方法能配对的是( )A.①Ⅰ②Ⅱ B.①Ⅲ②ⅠC.①Ⅱ②Ⅰ D.①Ⅲ②Ⅱ[答案] C[解析] ①容器与抽取的样本无关且总体数比较大故可
单项填空从ABCD四个选项中选出可以填入空白处的最佳选项并在答题卡上将该项涂黑1.____some doubt among scientists about the cause of cancer.A. It exists B. There exists C. There is existing D. It is existing2.Helen s
单项填空从ABCD四个选项中选出可以填入空白处的最佳选项并在答题卡上将该项涂黑1. He is very stubborn it is impossible to argue _____________ what he doesnt want to.A. with him about B. against him about C. him into doing D. h
单项填空从ABCD四个选项中选出可以填入空白处的最佳选项并在答题卡上将该项涂黑1. Why dont you go for ___ walk Itll give you ___ appetite for your lunch.A. a B. a an C. an D. 2. ---What attracts people to California is its pleas
单项填空从ABCD四个选项中选出可以填入空白处的最佳选项并在答题卡上将该项涂黑1. —What have you been busy with these days —I ______ that the speech contest has been brought forward so I ______ for it.A. was informed have been preparing
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