18.(x+y)(x2+x+y)5的展开式中,x5y2的系数为( )
| A. | 30 | B. | 40 | C. | 50 | D. | 60 |
17.设函数f(x)=sin(2x+φ)(其中0<φ<π)满足f(-x)=f(x),则( )
| A. | f(x)在$(0,\frac{π}{2})$单调递减 | B. | f(x)在$(\frac{π}{4},\frac{3π}{4})$单调递减 | ||
| C. | f(x)在$(0,\frac{π}{2})$单调递增 | D. | f(x)在$(\frac{π}{4},\frac{3π}{4})$单调递增 |
16.已知数列{an}是等差数列,a1=1,a3=5,则公差d等于( )
| A. | -2 | B. | -1 | C. | 2 | D. | 1 |
14.设集合A=$\left\{{\left.x\right|y=\sqrt{1-x}}\right\}$,集合B={y|y=x2-4x+3},则集合A∩B=( )
| A. | (-∞,1] | B. | [-1,+∞) | C. | [-1,1] | D. | ∅ |
13.已知m、n是两条不重合的直线,α、β、γ是三个两两不重合的平面,给出下列四个命题:
①若m⊥α,m⊥β,则α∥β;
②若m?α,n?β,m∥n,则α∥β;
③若α⊥γ,β⊥γ,则α∥β;
④若m、n是异面直线,m?α,m∥β,n?β,n∥α,则α∥β
其中真命题是( )
①若m⊥α,m⊥β,则α∥β;
②若m?α,n?β,m∥n,则α∥β;
③若α⊥γ,β⊥γ,则α∥β;
④若m、n是异面直线,m?α,m∥β,n?β,n∥α,则α∥β
其中真命题是( )
| A. | ①和② | B. | ①和③ | C. | ①和④ | D. | ③和④ |
12.已知数列{an}的通项公式是an=(-1)n(n+2),则a1+a2+…+a100等于( )
0 234242 234250 234256 234260 234266 234268 234272 234278 234280 234286 234292 234296 234298 234302 234308 234310 234316 234320 234322 234326 234328 234332 234334 234336 234337 234338 234340 234341 234342 234344 234346 234350 234352 234356 234358 234362 234368 234370 234376 234380 234382 234386 234392 234398 234400 234406 234410 234412 234418 234422 234428 234436 266669
| A. | -50 | B. | -100 | C. | 50 | D. | 100 |