15.若α∈[-$\frac{π}{4},\frac{π}{4}$],β∈[-$\frac{π}{8}$,$\frac{π}{8}$],且满足$\left\{\begin{array}{l}{{α}^{3}+sinα-2k=0}\\{4{β}^{3}+sinβcosβ+k=0}\end{array}\right.$,k∈R,则cos(α+2β)的值为( )
| A. | $\frac{\sqrt{3}}{3}$ | B. | $\frac{\sqrt{3}}{2}$ | C. | 1 | D. | $\frac{1}{2}$ |
14.等差数列{an}的前n项和为Sn(n∈N*),若当首项a1和公差d变化时,a7+a9+a11是一个定值,则下列选项中为定值的是( )
| A. | S15 | B. | S16 | C. | S17 | D. | S18 |
9.将函数f(x)=$\sqrt{3}$sin(ωx-$\frac{π}{3}$)的图象分别向左和向右移动$\frac{π}{3}$之后的图象的对称中心重合,则正实数ω的最小值是( )
0 227792 227800 227806 227810 227816 227818 227822 227828 227830 227836 227842 227846 227848 227852 227858 227860 227866 227870 227872 227876 227878 227882 227884 227886 227887 227888 227890 227891 227892 227894 227896 227900 227902 227906 227908 227912 227918 227920 227926 227930 227932 227936 227942 227948 227950 227956 227960 227962 227968 227972 227978 227986 266669
| A. | $\frac{2}{3}$ | B. | $\frac{1}{2}$ | C. | $\frac{3}{2}$ | D. | $\frac{1}{3}$ |