8.排球比赛的规则是5局3胜制(无平局),甲在每局比赛获胜的概率都相等为$\frac{2}{3}$,前2局中乙队以2:0领先,则最后乙队获胜的概率是( )
| A. | $\frac{4}{9}$ | B. | $\frac{8}{27}$ | C. | $\frac{19}{27}$ | D. | $\frac{40}{81}$ |
4.已知x5(x+3)3=a8(x+1)8+a7(x+1)7+…+a1(x+1)+a0,则7a7+5a5+3a3+a1=( )
| A. | -16 | B. | -8 | C. | 8 | D. | 16 |
2.若函数$f(x)=sin(ωx+\frac{π}{4})(0<ω<2)$的图象关于直线$x=\frac{π}{6}$对称,则f(x)的最小正周期为( )
0 227697 227705 227711 227715 227721 227723 227727 227733 227735 227741 227747 227751 227753 227757 227763 227765 227771 227775 227777 227781 227783 227787 227789 227791 227792 227793 227795 227796 227797 227799 227801 227805 227807 227811 227813 227817 227823 227825 227831 227835 227837 227841 227847 227853 227855 227861 227865 227867 227873 227877 227883 227891 266669
| A. | $\frac{2π}{3}$ | B. | $\frac{4π}{3}$ | C. | 2π | D. | $\frac{8π}{3}$ |