lim(x→0) [(1+x)/(1-x)]^(1/x)
=lim(x→0) [(1-x+2x)/(1-x)]^(1/x)
=lim(x→0) [1+2x/(1-x)]^(1/x)
=lim(x→0) [1+2x/(1-x)]^[(1-x)/2x]*2/(1-x)
∵lim(x→0) [1+2x/(1-x)]^[(1-x)/2x]=e
∵lim(x→0) 2/(1-x)=2/(1-0)=2
∴原式=e²
lim(x→0) [(1+x)/(1-x)]^(1/x)
=lim(x→0) [(1-x+2x)/(1-x)]^(1/x)
=lim(x→0) [1+2x/(1-x)]^(1/x)
=lim(x→0) [1+2x/(1-x)]^[(1-x)/2x]*2/(1-x)
∵lim(x→0) [1+2x/(1-x)]^[(1-x)/2x]=e
∵lim(x→0) 2/(1-x)=2/(1-0)=2
∴原式=e²