14.已知集合A={-2,0,2},B={x|x2-x-2=0},则∁A(A∩B)=( )
| A. | {-2,0} | B. | {2,0} | C. | {-2,-1,0} | D. | {2,1,0} |
13.已知实数x,y,z满足:x+y-6=0,z2+9=xy,则x2+$\frac{1}{3}$y2=( )
| A. | 6 | B. | 12 | C. | 18 | D. | 36 |
7.在△ABC中,|AB|=4,|AC|=2,∠A=60°,|BC|=( )
| A. | $4\sqrt{2}$ | B. | $4\sqrt{3}$ | C. | $2\sqrt{3}$ | D. | $2\sqrt{2}$ |
6.⊙Ox2+y2=25的圆心O到直线3x+4y+5=0的距离等于( )
| A. | 1 | B. | 3 | C. | 5 | D. | 7 |
5.从编号依次为1,2,3….100的个体中,用系统抽样方法抽取5个个体,则抽出的编号可能为( )
0 229946 229954 229960 229964 229970 229972 229976 229982 229984 229990 229996 230000 230002 230006 230012 230014 230020 230024 230026 230030 230032 230036 230038 230040 230041 230042 230044 230045 230046 230048 230050 230054 230056 230060 230062 230066 230072 230074 230080 230084 230086 230090 230096 230102 230104 230110 230114 230116 230122 230126 230132 230140 266669
| A. | 5,15,25,35,45 | B. | 25,45,65,85,100 | C. | 10,30,50,70,90 | D. | 23,33,45,53,63 |