16.已知集合A={-3,-2,-1,0,1,2},B={x|(x+3)(x-1)<0},则A∩B=( )
| A. | {0,1,2} | B. | {-2,-1,0} | C. | {-3,-2,-1,0,1} | D. | {0,1,2,3} |
14.命题“若a2+b2=0,则a=b=0”的逆否命题是( )
| A. | 若a≠b≠0,则a2+b2≠0 | B. | 若a=b≠0,则a2+b2≠0 | ||
| C. | 若a≠0且b≠0,则a2+b2≠0 | D. | 若a≠0或b≠0,则a2+b2≠0 |
11.若函数y=ex+ax有大于零的极值点,则实数a的取值范围是( )
| A. | a>-1 | B. | $a>-\frac{1}{e}$ | C. | a<-1 | D. | $a<-\frac{1}{e}$ |
10.已知函数f(x)=x•cosx,则$f'({\frac{π}{2}})$的值为( )
| A. | $-\frac{π}{2}$ | B. | $\frac{π}{2}$ | C. | 1 | D. | -1 |
9.把89化成二进制数使( )
| A. | 100100 | B. | 10010 | C. | 10100 | D. | 1011001 |
8.
太原市某时段100辆汽车通过祥云桥时,时速的频率分布直方图如图所示,则时速在[30,40]的汽车约有( )
0 236528 236536 236542 236546 236552 236554 236558 236564 236566 236572 236578 236582 236584 236588 236594 236596 236602 236606 236608 236612 236614 236618 236620 236622 236623 236624 236626 236627 236628 236630 236632 236636 236638 236642 236644 236648 236654 236656 236662 236666 236668 236672 236678 236684 236686 236692 236696 236698 236704 236708 236714 236722 266669
| A. | 30辆 | B. | 35辆 | C. | 40辆 | D. | 50辆 |