1.若复数z=(a2+2a-3)+(a-3)i为纯虚数(i为虚数单位),则a=( )
| A. | -3 | B. | -3或1 | C. | 3或-1 | D. | 1 |
20.已知A={x|-1<x<2},B={x|x≥a},若A∩B=∅,则a实数的取值范围( )
| A. | a≤-1 | B. | a≥-1 | C. | a≥2 | D. | -1<a<2 |
19.过抛物线y2=4x的焦点F的直线交抛物线于A,B两点,点O是原点,若A点到准线的距离为3,则△AOB的面积为( )
| A. | $\frac{{\sqrt{2}}}{2}$ | B. | $\sqrt{2}$ | C. | $\frac{{3\sqrt{2}}}{2}$ | D. | 2$\sqrt{2}$ |
18.若函数f(x)的定义域为[-1,1],则f(2x+1)的定义域为( )
0 234204 234212 234218 234222 234228 234230 234234 234240 234242 234248 234254 234258 234260 234264 234270 234272 234278 234282 234284 234288 234290 234294 234296 234298 234299 234300 234302 234303 234304 234306 234308 234312 234314 234318 234320 234324 234330 234332 234338 234342 234344 234348 234354 234360 234362 234368 234372 234374 234380 234384 234390 234398 266669
| A. | [0,1] | B. | [-1,0] | C. | [-1,1] | D. | [-3,1] |