10.正方形ABCD的边长为6,点E,F分别在边AD,BC上,且DE=EA,CF=2FB,如果对于常数λ,在正方形ABCD的四条边上(不含顶点)有且只有6个不同的点P,使得$\overrightarrow{PE}•\overrightarrow{PF}=λ$成立,那么λ的取值范围为( )
| A. | $(-3,-\frac{1}{4})$ | B. | (-3,3) | C. | $(-\frac{1}{4},3)$ | D. | (3,12) |
9.已知等比数列{an}中,各项都是正数,前n项和为Sn,且${a_2},\frac{1}{2}{a_3},{S_2}$成等差数列,则公比q等于( )
| A. | $1+\sqrt{2}$ | B. | $1-\sqrt{2}$ | C. | $3+2\sqrt{2}$ | D. | $3-2\sqrt{2}$ |
8.已知集合A={x|x2-1≤0},B={x|lnx<0},则A∪B=( )
| A. | {x|x≤1} | B. | {x|0<x<1} | C. | {x|-1≤x≤1} | D. | {x|0≤x≤1} |
7.某几何体的三视图如图所示(单位:cm),则这个几何体的体积为( )

| A. | 16cm3 | B. | 20cm3 | C. | 24cm3 | D. | 30cm3 |
3.已知正项数列{an}的前n项和为Sn,若{an}和{$\sqrt{{S}_{n}}$}都是等差数列,且公差相等,则S100=( )
0 227668 227676 227682 227686 227692 227694 227698 227704 227706 227712 227718 227722 227724 227728 227734 227736 227742 227746 227748 227752 227754 227758 227760 227762 227763 227764 227766 227767 227768 227770 227772 227776 227778 227782 227784 227788 227794 227796 227802 227806 227808 227812 227818 227824 227826 227832 227836 227838 227844 227848 227854 227862 266669
| A. | 50 | B. | 100 | C. | 1500 | D. | 2500 |