9.“!”是一种数学运算符号,并且1!=1,2!=1×2,3!=1×2×3,4!=1×2×3×4,…,则$\frac{2016!}{2015!}$的值为( )
| A. | 2013 | B. | 2014 | C. | 2015 | D. | 2016 |
5.$\sqrt{{{(-5)}^2}}$的算术平方根是( )
| A. | ±5 | B. | 5 | C. | -5 | D. | $\sqrt{5}$ |
4.下列各式中,正确的是( )
| A. | $\sqrt{{{(-2)}^2}}=-2$ | B. | $\sqrt{3^2}=9$ | C. | $-\sqrt{9}=-3$ | D. | $\sqrt{-9}=-3$ |
3.下面选项中是勾股数的一组是( )
| A. | 32,42,52 | B. | 20,28,35 | C. | 1.5,5,2.5 | D. | 7,24,25 |
2.下面的四组数:①7,24,25;②0.3,0.4,0.5;③1.5,2,2.5;④6,8,9.是勾股数的有几组( )
0 308956 308964 308970 308974 308980 308982 308986 308992 308994 309000 309006 309010 309012 309016 309022 309024 309030 309034 309036 309040 309042 309046 309048 309050 309051 309052 309054 309055 309056 309058 309060 309064 309066 309070 309072 309076 309082 309084 309090 309094 309096 309100 309106 309112 309114 309120 309124 309126 309132 309136 309142 309150 366461
| A. | 1 组 | B. | 2组 | C. | 3组 | D. | 4组 |