1.已知集合M={x∈R|x2+2x=0},N={2,0},则M∩N=( )
| A. | {0} | B. | {2} | C. | ∅ | D. | {-2,0,2} |
17.在四面体S-ABC中,$AB⊥BC,AB=BC=\sqrt{2},SA=SC=2$,二面角S-AC-B的余弦值为$-\frac{{\sqrt{3}}}{3}$,则该四面体外接球的表面积是( )
| A. | $8\sqrt{6}π$ | B. | $\sqrt{6}π$ | C. | 24π | D. | 6π |
16.已知圆O为Rt△ABC的外接圆,AB=AC,BC=4,过圆心O的直线l交圆O于P,Q两点,则$\overrightarrow{BP}•\overrightarrow{CQ}$的取值范围是( )
0 236956 236964 236970 236974 236980 236982 236986 236992 236994 237000 237006 237010 237012 237016 237022 237024 237030 237034 237036 237040 237042 237046 237048 237050 237051 237052 237054 237055 237056 237058 237060 237064 237066 237070 237072 237076 237082 237084 237090 237094 237096 237100 237106 237112 237114 237120 237124 237126 237132 237136 237142 237150 266669
| A. | [-8,-1] | B. | [-8,0] | C. | [-16,-1] | D. | [-16,0] |