12.已知2sinα+cosα=0,则sin2α-3cos2α-sin2α=( )
| A. | -$\frac{17}{5}$ | B. | -$\frac{17}{4}$ | C. | -$\frac{16}{5}$ | D. | -2 |
11.已知k∈Z,$\overrightarrow{AB}$=(k,1),$\overrightarrow{AC}$=(2,4),若|$\overrightarrow{AB}$|≤$\sqrt{17}$,则∠B是直角的概率是( )
| A. | $\frac{4}{9}$ | B. | $\frac{1}{3}$ | C. | $\frac{2}{9}$ | D. | $\frac{1}{9}$ |
10.已知某几何体的三视图如图表 所示,则该几何体的体积为( )

| A. | $\frac{16}{3}$ | B. | $\frac{64}{3}$ | C. | $\frac{80}{3}$ | D. | $\frac{43}{3}$ |
8.已知全集U=R,若集合A={y|y=3-2-x},B={x|$\frac{x-2}{x}$≤0},则A∩∁UB=( )
| A. | (-∞,0)∪[2,3) | B. | (-∞,0]∪(2,3) | C. | [0,2) | D. | [0,3) |
6.函数f(x)=$\sqrt{x+1}+\frac{1}{x}$的定义域为( )
0 234644 234652 234658 234662 234668 234670 234674 234680 234682 234688 234694 234698 234700 234704 234710 234712 234718 234722 234724 234728 234730 234734 234736 234738 234739 234740 234742 234743 234744 234746 234748 234752 234754 234758 234760 234764 234770 234772 234778 234782 234784 234788 234794 234800 234802 234808 234812 234814 234820 234824 234830 234838 266669
| A. | [-1,0)∪(0,+∞) | B. | (-1,0)∪(0,+∞) | C. | [-1,+∞) | D. | (0,+∞) |