X→0+ means that X approaches 0 from the right, that is, X >；; 0,

X→0- means that X approaches 0 from the left, which is X.

2. Let u = 1/x, lim.

= lim & ltu→+∞& gt； ue^(-u)= lim & lt； u→+∞& gt； U/e u = 0, choose B.

3. Let u = 1/x, lim.

= lim & ltu→-∞& gt； Ue (-u) =∞, choose C.

1 It can be seen that lim < x→0>；; E (- 1/x)/x does not exist. Option d