[单选题]已知a,b是平面内两个互相垂直的单位向量,若向量c满足(a-c)·(b-c)=0,则|c|的最大值是A.1B.2 C.D.
[单选题]__________my efforts at persuasion,he wouldn’t agree.A.Apart fromB.In spite ofC.Because ofD.Although
[单选题]— Alice, have you heard that the grocery store down the street was ______, and nearly all the things there were stolen— God! Really? That’s horrible!A.broken downB.broken upC.broken intoD.broken out
[单选题]The aim of the government is to make every citizen better off,____, to help them live a happy life.A.as a resultB.for a startC.for one thingD.in other words
[单选题]Economic growth in the world remains weak throughout 2013 and it is hoped that it will___gradually in 2014.A.break upB.pick upC.make outD.work out
[单选题]0<x<3是x-1<2成立的( )A.充分不必要条件B.必要不充分条件C.充要条件D.既不充分也不必要条件
[计算题]已知双曲线C:,(1)求双曲线C的渐近线方程;(2)已知点M的坐标为(0,1),设P是双曲线C上的点,Q是点P关于原点的对称点,记,求λ的取值范围;(3)已知点D,E,M的坐标分别为(-2,-1),(2,-1),(0,1),P为双曲线C上在第一象限内的点.记l为经过原点与点P的直线,s为△DEM截直线l所得线段的长.试将s表示为直线l的斜率k的函数.
[单选题]已知、B、C是单位圆上三个互不相同的点.若ABACI,则ABlAC的最小值是( )A..B.4.C.2.D.3-4.
[单选题]Nowadays it seems to some of us that it is feeling, not just money, that is what really ________. A.countsB.staysC.meansD.grows
[计算题]椭圆C中心在原点,焦点在x轴上,一条经过点(3,)且方向向量为a=(-2,)的直线l交椭圆于A,B两点,交x轴于M点,又AM=2B,(Ⅰ)求直线l的方程;(Ⅱ)求椭圆C长轴的取值范围.
[单选题]6=30是cos26=2的( )A.充分不必要条件B.必要不充分条件C.充要条件D.既不充分又不必要条件
[单选题]设M={x1x>2}.P={x1x<3},则“x∈M,或x∈P”是“x∈M∩P”的( )A.必要不充分条件B.充分不必要条件C.充要条件D.既不充分也不必要条件
[单选题]命题“对任意x∈R都有x2≥1”的否定是( )A.对任意x∈R,都有x2<1B.不存在x∈R,使得x2<1C.存在x∈R,使得x≥1D.存在x∈R,使得x<1
[单选题]He is sure to ________ with the help of Mrs. Li.A.make a progressB.make progressesC.make the progressD.make progress
[计算题]设命题p:函数f(x)=2|x﹣a|在区间(1,+∞)上单调递增;命题q:a∈{y|y=?16-4,x∈R},如果“p且q”是假命题,“p或q”是真命题,求实数a的取值范围.
[单选题]— What is that building ______ construction — It looks like a hospital..A.underB.onC.inD.through
[单选题]In dealing with public relations, we should make every effort to prevent the _____ in personality.A.contactB.contrastC.conflictD.connection
[单选题]已知“x>A”是“<1x+1”的充分不必要条件,则k的取值范围是( )A.[2,+)B.[1,+)C.(2,+)D.(一,-1]
[单选题]More and more high-rise buildings have been built in big cities________ space.A.in search ofB.in place ofC.for lack ofD.in memory of
[单选题]Im sure that middle school students will benefit ________ taking exercise every day, which is ________ great benefit ________ their health.[ ]A. by; of; atB. from; of; toC. of; by; toD. by; from; at
[单选题]已知命题p:x≥0,2x=3,则 []A. p:x<0,2x≠3 B. p:x≥0,2x≠3 C. p:x≥0,2x≠3 D. p:x<0,2x≠3