8.$\frac{{sin\frac{11π}{4}•cos(-\frac{2π}{3})}}{{tan(-\frac{23π}{3})}}+\frac{{sin(-\frac{21π}{4})}}{{cos(\frac{17π}{6})}}$化简的结果是( )
A. | $-\frac{{5\sqrt{6}}}{12}$ | B. | $\frac{{\sqrt{6}}}{4}$ | C. | $-\frac{{\sqrt{6}}}{4}$ | D. | $\frac{{5\sqrt{6}}}{12}$ |
7.函数f(x)=x+lnx-2零点所在区间为( )
A. | (0,1) | B. | (e,e2) | C. | (1,e) | D. | $(\frac{1}{2},1)$ |
4.若函数f(x)=x2-2kx+5在[2,4]上具有单调性,则实数k的取值范围是( )
A. | [4,+∞) | B. | (-∞,-2] | C. | [2,+∞) | D. | (-∞,2]∪[4,+∞) |
3.设函数$f(x)=\left\{{\begin{array}{l}{x+1,x≤-2}\\{{x^2}+2x,-2<x<2}\\{2x-1,x≥2}\end{array}}\right.$,若f(a)=3,则a等于( )
A. | 1 | B. | 1或2 | C. | 2 | D. | 3 |
2.已知A={-2,2010,x2-1},B={0,2010,x2-3x},且A=B,则x的值为( )
0 251485 251493 251499 251503 251509 251511 251515 251521 251523 251529 251535 251539 251541 251545 251551 251553 251559 251563 251565 251569 251571 251575 251577 251579 251580 251581 251583 251584 251585 251587 251589 251593 251595 251599 251601 251605 251611 251613 251619 251623 251625 251629 251635 251641 251643 251649 251653 251655 251661 251665 251671 251679 266669
A. | 1 | B. | 0 | C. | -1 | D. | -1,1 |