10.若非零向量$\overrightarrow{a}$,$\overrightarrow{b}$满足|$\overrightarrow{a}$=2|$\overrightarrow{b}$|=|$\overrightarrow{a}$-3$\overrightarrow{b}$|,则$\overrightarrow{a}$,$\overrightarrow{b}$夹角的余弦值为( )
| A. | $-\frac{3}{8}$ | B. | $\frac{3}{8}$ | C. | $-\frac{3}{4}$ | D. | $\frac{3}{4}$ |
9.在复平面内,复数z1对应的点与复数z2=$\frac{3+2i}{i}$(i为虚数单位)对应的点关于虚轴对称,则z1等于( )
| A. | -2-3i | B. | -2+3i | C. | 2-3i | D. | 2+3i |
4.定义在[0,+∞)的函数f(x)的导函数为f′(x),对于任意的x≥0,恒有f′(x)>f(x),a=e3f(2),b=e2f(3),则a,b的大小关系是( )
| A. | a>b | B. | a<b | C. | a=b | D. | 无法确定 |
3.已知实数x,y满足$\left\{\begin{array}{l}{x≥0}\\{y≥0}\\{x+2y≤2}\end{array}\right.$,若目标函数z=x-y的最大值为a,最小值为b,则(a-bt)6展开式中t4的系数为( )
| A. | 200 | B. | 240 | C. | -60 | D. | 60 |
2.
如图,若在矩阵OABC中随机撒一粒豆子,则豆子落在图中阴影部分的概率为( )
0 227507 227515 227521 227525 227531 227533 227537 227543 227545 227551 227557 227561 227563 227567 227573 227575 227581 227585 227587 227591 227593 227597 227599 227601 227602 227603 227605 227606 227607 227609 227611 227615 227617 227621 227623 227627 227633 227635 227641 227645 227647 227651 227657 227663 227665 227671 227675 227677 227683 227687 227693 227701 266669
| A. | 1-$\frac{2}{π}$ | B. | $\frac{2}{π}$ | C. | $\frac{2}{{π}^{2}}$ | D. | 1-$\frac{2}{{π}^{2}}$ |