[单选题]若向量a、b满足|a|=|b|=1,a与b的夹角为60°,则a·a+a·b=A.B.C.1+D.2
[单选题]设a>0且a≠1,命题:函数f(x)=a在R上是增函数 ,命题:函数g(x)=(a-2)x在R上是减函数,则是的( )A.充分不必要条件B.必要不充分条件 C.充分必要条件D.既不充分也不必要条件
[单选题]The old couple dont want to _______ their son and still live in the countryside although their son urged them to move to the city and live with his family several times.A.botherB.disturbC.interruptD.dislike
[单选题]The school _______ I graduated is no longer what it used to be. [ ]A. from whereB. whichC. in which D. from which
[单选题]已知2,,a+b,则(? )A.√13B.√15C.17D.7
[单选题]设向量a=(l, cos 6)与b=(-12cos6)垂直,则cos 26等于( )A.22B.2C.2D.-1
[单选题]对于任意实数a、b、c、d,下列命题中,真命题为①若a>b,c≠0,则ac>bc;②若a>b,则ac2>bc2;③若ac2>bc2,则a>b;④若a>b,则; [ ]A.①B.②C.③ D.④
[计算题]已知命题P:“x∈R,x2+(m﹣1)x+1≥0”是真命题;命题Q:方程x25In山下飞表示双曲线,若P∨Q为假命题,求实数m的取值范围.
[单选题]-- Can you lend me the book Twilight by Stephenie Meyer-- Sorry. I returned it to the library just now. Maybe it is still _____.A.availableB.affordableC.acceptableD.valuable
[单选题]This important lesson by Professor Wang teaches primary students how to ______ themselves from danger.A.pretendB.preventC.prepareD.protect
[单选题]设p和q是两个简单命题,若p是q的充分不必要条件,则p是q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
[单选题]The theory should____ practice, or it could just be something useless.A.be applied ofB.is applied forC.be applied forD.be applied to
[单选题]When a person is _____, talking with others often helps him feel better.[ ]A. in trouble B. in danger C. in silence D. in a trouble
[单选题]The two sides ____a series of compromise suggestions and then signed the contract.A.made outB.worked outC.put outD.picked out
[单选题]若l、m、n是互不相同的空间直线,α、β是不重合的平面,则下列命题中为真命题的是 ( )A.若α∥β,lα,nβ,则l∥n B.若α⊥β,lα,则l⊥β C.若l⊥n,m⊥n,则l∥mD.若l⊥α,l∥β,则α⊥β
[单选题]The meal over, the managers went back to the meeting room to ________ their discussion.A.put awayB.take downC.look overD.carry on
[计算题]设命题p:函数f(x)=(a-2)x2是R上的减函数,命题q:函数f(x)=x2﹣4x+3在[0,a]的值域为[﹣1,3].若“p且q”为假命题,“p或q”为真命题,求a的取值范围.
[单选题]Everything on the news ________ a whole new meaning when you have a personal connection with the people.A.takes upB.takes onC.takes away D.takes off
[单选题]已知a,b∈R,则“b≥0”是“(a+1)2+b≥0”的( )A.充分不必要条件B.必要不充分条件C.充分必要条件D.既不充分也不必要条件
[计算题]已知命题:“x∈{x|-1≤x≤1},都有不等式x2-x-m< 0成立”是真命题,(1)求实数m的取值集合B;(2)设不等式(x-3a)(x-a-2)<0的解集为A,若x∈A是x∈B的充分不必要条件,求a的取值范围.
[计算题]判断下列命题的真假.(1) 对角线不相等的四边形不是等腰梯形;(2) 若xA∩B,则x A且x B;(3)若x2+y2≠0,则xy≠0;(4)若x≠y或x≠-y,则|x|≠|y|.