问题
选择题
若
|
答案
A：若f（x）=x2，则lim x→0
=f(x)(x-1) x2+x lim x→0
=x2(x-1) x2+x lim x→0
=0，满足条件x(x-1) x+1
B：若f（x）=|x|，则lim x→0
=f(x)(x-1) x2+x lim x→0
=|x|(x-1) x(x+1)
，极限不存在-1，x＞0 1，x＜0
C：若f（x）=x，则lim x→0
=f(x)(x-1) x2+x lim x→0
=-1，存在极限x(x-1) x(x+1)
D：若f（x）=-x，则lim x→0
=f(x)(x-1) x2+x lim x→0
=1，存在极限-x(x-1) x(x+1)
故选B