8.计算sin245°+tan60°•cos30°值为( )
| A. | 2 | B. | $\frac{3}{2}$ | C. | 1 | D. | $\frac{1}{2}$ |
4.下列运算正确的是( )
| A. | 2a-a=2 | B. | (-a2)3=-a6 | C. | x6÷x3=x2 | D. | (x+y)2=x2+y2 |
3.下列四个数中,比-2小的数是( )
0 284046 284054 284060 284064 284070 284072 284076 284082 284084 284090 284096 284100 284102 284106 284112 284114 284120 284124 284126 284130 284132 284136 284138 284140 284141 284142 284144 284145 284146 284148 284150 284154 284156 284160 284162 284166 284172 284174 284180 284184 284186 284190 284196 284202 284204 284210 284214 284216 284222 284226 284232 284240 366461
| A. | -1 | B. | 0 | C. | -3 | D. | -$\frac{1}{2}$ |