5.设函数f(x)=x2+2cosx,若f(x1)>f(x2),则下列不等式一定成立的是( )
| A. | x1>x2 | B. | |x1|<|x2| | C. | x1>|x2| | D. | x12>x22 |
4.已知函数f(x)=ex+4x-3的零点为x0,则x0所在的区间是( )
| A. | (0,$\frac{1}{4}$) | B. | ($\frac{1}{4}$,$\frac{1}{2}$) | C. | ($\frac{1}{2}$,$\frac{3}{4}$) | D. | ($\frac{3}{4}$,1) |
3.设变量x,y满足约束条件$\left\{\begin{array}{l}{x+2y-3≤0}\\{x+3y-3≥0}\\{y-1≤0}\end{array}\right.$,则目标函数z=2x+y的最大值为( )
| A. | 1 | B. | 2 | C. | 3 | D. | 6 |
2.已知向量$\overrightarrow{m}$=(a,-2),$\overrightarrow{n}$=(1,1-a),且$\overrightarrow{m}$∥$\overrightarrow{n}$,则实数a的值为( )
0 233498 233506 233512 233516 233522 233524 233528 233534 233536 233542 233548 233552 233554 233558 233564 233566 233572 233576 233578 233582 233584 233588 233590 233592 233593 233594 233596 233597 233598 233600 233602 233606 233608 233612 233614 233618 233624 233626 233632 233636 233638 233642 233648 233654 233656 233662 233666 233668 233674 233678 233684 233692 266669
| A. | 2或-1 | B. | -1 | C. | 2 | D. | -2 |