9.已知向量$\overrightarrow{a}$,$\overrightarrow{b}$满足$\overrightarrow{a}$•($\overrightarrow{a}$+$\overrightarrow{b}$)=5,且|$\overrightarrow{a}$|=2|$\overrightarrow{b}$|=2,则向量$\overrightarrow{a}$,$\overrightarrow{b}$的夹角为( )
| A. | $\frac{π}{6}$ | B. | $\frac{π}{3}$ | C. | $\frac{π}{4}$ | D. | -$\frac{π}{3}$ |
6.已知向量$\overrightarrow a$=(x,$\sqrt{3}}$),$\overrightarrow b$=(x,-$\sqrt{3}}$),若(2$\overrightarrow a$+$\overrightarrow b}$)⊥$\overrightarrow b$,则|${\overrightarrow a}$|=( )
| A. | 1 | B. | $\sqrt{2}$ | C. | $\sqrt{3}$ | D. | 2 |
5.已知复数z满足(2+i)z=3+4i,则z=( )
| A. | 2+i | B. | -2-i | C. | 2-i | D. | -2+i |
4.设集合A={x|x2-3x≥0},B={x|x<1},则A∩B=( )
| A. | (-∞,0]∪[3,+∞) | B. | (-∞,1)∪[3,+∞) | C. | (-∞,1) | D. | (-∞,0] |
3.已知x=ln π,y=log52,z=log${\;}_{\frac{1}{2}}}$e则( )
| A. | x<y<z | B. | z<x<y | C. | z<y<x | D. | y<z<x |
2.下列函数中既是偶函数,又在区间(0,+∞)上是增函数的是( )
| A. | y=x3 | B. | y=|x|+1 | C. | y=-x2+1 | D. | $y=\frac{1}{x^2}$ |
20.设数集M={x|m≤x≤m+$\frac{3}{4}$},N={x|n-$\frac{1}{3}$≤x≤n},P={x|0≤x≤1},且M,N都是集合P的子集,如果把b-a叫做集合{x|a≤x≤b}的“长度”,那么集合M∩N的“长度”的最小值是( )
0 234340 234348 234354 234358 234364 234366 234370 234376 234378 234384 234390 234394 234396 234400 234406 234408 234414 234418 234420 234424 234426 234430 234432 234434 234435 234436 234438 234439 234440 234442 234444 234448 234450 234454 234456 234460 234466 234468 234474 234478 234480 234484 234490 234496 234498 234504 234508 234510 234516 234520 234526 234534 266669
| A. | $\frac{1}{3}$ | B. | $\frac{2}{3}$ | C. | $\frac{1}{12}$ | D. | $\frac{5}{12}$ |