8.对于集合M,定义函数fM(x)=$\left\{\begin{array}{l}{-1,x∈M}\\{1,x∉M}\end{array}\right.$,对于两个集合M、N,定义集合M⊕N={x|fM(x)•fN(x)=-1},已知A={2,4,6,8,10},B={1,2,4,5,6,8,9},则集合A⊕B=( )
| A. | {1,5,9,10} | B. | {1,5,9} | C. | {2,4,6} | D. | {2,4,6,8} |
7.已知向量$\overrightarrow{OA}$=(k,12),$\overrightarrow{OB}$=(4,5),$\overrightarrow{OC}$=(-k,10),且A、B、C三点共线,则k=( )
| A. | -$\frac{4}{3}$ | B. | $\frac{4}{3}$ | C. | -$\frac{2}{3}$ | D. | $\frac{2}{3}$ |
6.把函数y=2sin(2x+$\frac{π}{4}$)的图象向右平移$\frac{π}{8}$个单位,再把所得图象上各点的横坐标扩大为原来的2倍,则所得的函数的解析式是( )
0 246579 246587 246593 246597 246603 246605 246609 246615 246617 246623 246629 246633 246635 246639 246645 246647 246653 246657 246659 246663 246665 246669 246671 246673 246674 246675 246677 246678 246679 246681 246683 246687 246689 246693 246695 246699 246705 246707 246713 246717 246719 246723 246729 246735 246737 246743 246747 246749 246755 246759 246765 246773 266669
| A. | y=2sin(x+$\frac{3π}{8}$) | B. | y=2sin(x+$\frac{π}{8}$) | C. | y=2sinx | D. | y=2sin4x |