19.(普通中学做)设实数x,y满足$\left\{\begin{array}{l}{x-y-2≤0}\\{x+3y-6≥0}\\{y-2≤0}\end{array}\right.$,则z=x+y的取值范围是( )
| A. | [4,6] | B. | [0,4] | C. | [2,4] | D. | [2,6] |
18.命题p:?x∈(-∞,0),2x>3x,则( )
| A. | p是假命题,¬p:?x0∈(-∞,0),2${\;}^{{x}_{0}}$≤3${\;}^{{x}_{0}}$ | |
| B. | p是假命题¬p:?x∈(-∞,0),2x>3x | |
| C. | p是真命题¬p:?x0∈(-∞,0),2${\;}^{{x}_{0}}$≤3${\;}^{{x}_{0}}$ | |
| D. | p是真命题¬p:?x∈(-∞,0),2x>3x |
17.等差数列{an}中,a1=2016,前n项和为Sn,若$\frac{{S}_{12}}{12}$-$\frac{{S}_{10}}{10}$=-2,则S2016=( )
| A. | 2014 | B. | 2015 | C. | 2016 | D. | 2017 |
16.将函数f(x)=cos2x的图象再向右平移$\frac{π}{4}$个单位长度,得到函数g(x)的图象,则y=g(x)图象的一条对称轴是直线( )
| A. | x=$\frac{π}{12}$ | B. | x=$\frac{π}{6}$ | C. | x=$\frac{π}{4}$ | D. | x=$\frac{2π}{3}$ |
15.复数z=$\frac{a+3i}{1+2i}$的实部与虚部相等,则实数a=( )
0 225345 225353 225359 225363 225369 225371 225375 225381 225383 225389 225395 225399 225401 225405 225411 225413 225419 225423 225425 225429 225431 225435 225437 225439 225440 225441 225443 225444 225445 225447 225449 225453 225455 225459 225461 225465 225471 225473 225479 225483 225485 225489 225495 225501 225503 225509 225513 225515 225521 225525 225531 225539 266669
| A. | 1 | B. | 2 | C. | $\sqrt{2}$ | D. | -1 |