1.一组正方形按如图所示的方式放置,其中顶点B1在y轴上,顶点C1、E1、E2、C2、E3、E4、C3…在x轴上,已知正方形A1B1C1D1的边长为1,∠B1C1O=60°,B1C1∥B2C2∥B3C3…,则正方形A2017B2017C2017D2017的边长是( )

| A. | ($\frac{1}{2}$)2016 | B. | ($\frac{1}{2}$)2017 | C. | ($\frac{\sqrt{3}}{3}$)2016 | D. | ($\frac{\sqrt{3}}{3}$)2017 |
19.把多项式m2-9m分解因式,结果正确的是( )
0 295131 295139 295145 295149 295155 295157 295161 295167 295169 295175 295181 295185 295187 295191 295197 295199 295205 295209 295211 295215 295217 295221 295223 295225 295226 295227 295229 295230 295231 295233 295235 295239 295241 295245 295247 295251 295257 295259 295265 295269 295271 295275 295281 295287 295289 295295 295299 295301 295307 295311 295317 295325 366461
| A. | m(m-9) | B. | (m+3)(m-3) | C. | m(m+3)(m-3) | D. | (m-3)2 |