14.已知集合M={y|y=x},N={x|x2+y2=1},则M∩N=( )
| A. | {($\frac{\sqrt{2}}{2}$,$\frac{\sqrt{2}}{2}$)} | B. | {(-$\frac{\sqrt{2}}{2}$,-$\frac{\sqrt{2}}{2}$),($\frac{\sqrt{2}}{2}$,$\frac{\sqrt{2}}{2}$)} | C. | (-1,1) | D. | [-1,1] |
13.在(1+x)+(1+x)2+(1+x)3+…+(1+x)11的展开式中,x3的系数是( )
| A. | 220 | B. | 165 | C. | 66 | D. | 55 |
12.在平面内,定点A,B,C,O满足$|{\overrightarrow{OA}}|=|{\overrightarrow{OB}}|=|{\overrightarrow{OC}}$|=2,$\overrightarrow{OA}•(\frac{AC}{{|{\overrightarrow{AC}}|}}-\frac{AB}{{|{\overrightarrow{AB}}|}})$=$\overrightarrow{OB}•(\frac{BC}{{|{\overrightarrow{BC}}|}}-\frac{BA}{{|{\overrightarrow{BA}}|}})=0$,动点P,M满足$|{\overrightarrow{AP}}|=1,\overrightarrow{PM}=\overrightarrow{MC},则{|{\overrightarrow{BM}}|^2}$的最大值是( )
| A. | $\frac{43}{4}$ | B. | $\frac{49}{4}$ | C. | $\frac{37}{4}$ | D. | $\frac{37}{2}$ |
11.集合A={1,2,a},B={2,3},若B?A,则实数a的值是( )
| A. | 1 | B. | 2 | C. | 3 | D. | 2或3 |
8.若存在两个正实数x,y使得等式3x+a(y-2ex)(lny-lnx)=0成立,其中e为自然对数的底数,则实数a的取值范围是( )
0 240355 240363 240369 240373 240379 240381 240385 240391 240393 240399 240405 240409 240411 240415 240421 240423 240429 240433 240435 240439 240441 240445 240447 240449 240450 240451 240453 240454 240455 240457 240459 240463 240465 240469 240471 240475 240481 240483 240489 240493 240495 240499 240505 240511 240513 240519 240523 240525 240531 240535 240541 240549 266669
| A. | (-∞,0) | B. | (0,$\frac{3}{e}$] | C. | [$\frac{3}{e}$,+∞) | D. | (-∞,0)∪[$\frac{3}{e}$,+∞) |