9.设等比数列{an}的前n项和为Sn,an>0,若S2=4,S4=40,则a5=( )
A. | 27 | B. | 28 | C. | 80 | D. | 81 |
3.某次语文考试中考生的分数X~N(80,100),则分数在60-100分的考生占总考生数的百分数为( )
A. | 68.26% | B. | 95.44% | C. | 99.74% | D. | 31.74% |
2.已知α,β∈($\frac{π}{2}$,π),cosα+sinβ>0,则( )
A. | α+β<π | B. | α+β>$\frac{3π}{2}$ | C. | α+β=$\frac{3π}{2}$ | D. | α+β<$\frac{3π}{2}$ |
1.满足A∪B={0,2}的集合A与B的组数为( )
0 247000 247008 247014 247018 247024 247026 247030 247036 247038 247044 247050 247054 247056 247060 247066 247068 247074 247078 247080 247084 247086 247090 247092 247094 247095 247096 247098 247099 247100 247102 247104 247108 247110 247114 247116 247120 247126 247128 247134 247138 247140 247144 247150 247156 247158 247164 247168 247170 247176 247180 247186 247194 266669
A. | 2 | B. | 5 | C. | 7 | D. | 9 |