【单选题】There are over 300 teachers in our school,_________ of them are women teachers.A.two fifthsB.seco
A.
7. There are over 300 teachers in our school,_________ of them are women teachers. A.two fifths
【简答题】已知函数f(x)=为奇函数,f(1)<f(3), 且不等式0≤f(x)≤的解集是{x|-2≤x≤-1或2≤x≤4}. (1)求a,b,c的值; (2)是否存在实数m使不等式f(-2+sinθ)<-m 2 +对一切θ∈R成立?若存在,求出m的取值范围;若不存在,请说明理由.
【单选题】We forgot to bring our tickets, but please let
A.
7. We forgot to bring our tickets, but please let usenter, _______. ( 全国 3) A. do you
【简答题】直流电源电路中,如果电压器副线圈的电压为U2,则经过半波整流后的电压Uo= U2; 若是桥式整流电路,整流后的电压Uo= U2;经过电容滤波,且RC=(3~5)T/2之后, 输出电压Uo= U2。
【单选题】10mol/L乙酸溶液的pH值为(已知KHAc=1.8×10-5)( )。
【简答题】7. Our teacher is
strict. Our teacher is fair.
【简答题】已知定义域为R的函数 是奇函数. (1)求a的值; (2)判断函数f(x)在R上的单调性,并证明你的结论. (3)是否存在实数k,对于任意t∈1,2],不等式f(t 2 ﹣2t)+f(2t 2 ﹣k)>0恒成立,若存在,求出实数k的取值范围,若不存在,说明理由。
【简答题】已知定义域为R的函数f(x)= - 2 x +b 2 x+1 +a 是奇函数. (1)求f(x); (2)是否存在最大的常数k,对于任意x实数都有f(x)>k,求出k;若不存在,说明理由. (3)若对任意的t∈R,不等式f(t 2 -2t)+f(2t 2 -k)<0恒成立,求k的取值范围.
【单选题】Our older generation used to advise us not to build ____ in the air, but that’s not realistic at
A.
7. Our older generation used to advise us not to build ____ in the air, but that’s not realistic at all. A.attics