2.
如图,小山岗的斜坡AC的坡角α=45°,在与山脚C距离200米的D处,测得山顶A的仰角为26.6°,小山岗的高AB约为(结果取整数,参考数据:sin26.6°=0.45,cos26.6°=0.89,tan26.6°=0.50)( )
| A. | 164m | B. | 178m | C. | 200m | D. | 1618m |
1.在半径为6的⊙O中,60°圆心角所对的扇形的面积为( )
| A. | 6π | B. | 4π | C. | 2π | D. | π |
19.在平面直角坐标系中,如果抛物线y=3x2不动,而把x轴、y轴分别向上、向右平移2个单位,那么在新坐标系中抛物线的解析式是( )
| A. | y=3(x-2)2+2 | B. | y=3(x+2)2-2 | C. | y=3(x-2)2+2 | D. | y=3(x+2)2+2 |
17.将抛物线y=-3x2-1向右平移1个单位长度,再向上平移1个单位长度后所得的抛物线的解析式为( )
| A. | y=-3(x-1)2 | B. | y=-3(x+1)2 | C. | y=-3(x-1)2+2 | D. | y=-3(x-1)2-2 |
16.-8的立方根是( )
0 283958 283966 283972 283976 283982 283984 283988 283994 283996 284002 284008 284012 284014 284018 284024 284026 284032 284036 284038 284042 284044 284048 284050 284052 284053 284054 284056 284057 284058 284060 284062 284066 284068 284072 284074 284078 284084 284086 284092 284096 284098 284102 284108 284114 284116 284122 284126 284128 284134 284138 284144 284152 366461
| A. | 2 | B. | 2$\sqrt{3}$ | C. | -$\frac{1}{2}$ | D. | -2 |