Question

下列四個(gè)函數(shù)中,與y=x表示同一函數(shù)的是(   )

A.y=                         B.y=

C.y=                           D.y=

Answer 1

B

解析:對(duì)于A,y==x(x≥0);

對(duì)于B,y==x(x∈R);

對(duì)于C,y==|x|=

對(duì)于D,y==x(x≠0).