12.已知函数f(x+1)是偶函数,当x∈(1,+∞)时,函数f(x)=sinx-x,设a=$f(-\frac{1}{2})$,b=f(3),c=f(0),则a、b、c的大小关系为( )
A. | a<b<c | B. | c<a<b | C. | b<c<a | D. | b<a<c |
11.已知{an}的通项an=23-n,则a1a2+a2a3+…+anan+1=( )
A. | $\frac{32}{3}$(1-4-n) | B. | $\frac{32}{3}$(1-2-n) | C. | 16(1-4-n) | D. | 16(1-2-n) |
10.在△ABC中,内角A,B,C的对边分别是a,b,c,若a2-b2=$\sqrt{3}$bc,sinC=$\sqrt{3}$sinB,则A=( )
A. | 30° | B. | 60° | C. | 90° | D. | 120° |
9.下列函数中,周期为π,且在$[\frac{π}{4},\frac{π}{2}]$上为减函数的是( )
0 246430 246438 246444 246448 246454 246456 246460 246466 246468 246474 246480 246484 246486 246490 246496 246498 246504 246508 246510 246514 246516 246520 246522 246524 246525 246526 246528 246529 246530 246532 246534 246538 246540 246544 246546 246550 246556 246558 246564 246568 246570 246574 246580 246586 246588 246594 246598 246600 246606 246610 246616 246624 266669
A. | $y=cos(x+\frac{5π}{2})$ | B. | $y=cos(2x+\frac{5π}{2})$ | C. | $y=sin(x+\frac{5π}{2})$ | D. | $y=sin(2x+\frac{5π}{2})$ |