Question

设[x]表示不大于x的最大整数, 则对任意实数x, y, 有

A.[－x]=－[x]

B.[x +]=[x]

C.[2x]=2[x]

D.

Answer

D

【解析】

代值法．

对A, 设x =" -" 1.8, 则[-x] = 1, ，-[x] =" 2," 所以A选项为假．

对B, 设x = 1.8, 则[x+] = 2, [x] =" 1," 所以B选项为假．

对C, 设x =" -" 1.4, [2x] =" [-2.8]" =" -" 3, 2[x] =" -" 4, 所以C选项为假．

故D选项为真．所以选D