lim(x->∞) [(e∧x+1)/(e^x-1)] arctanx
=(π/2). lim(x->∞) [(e∧x+1)/(e^x-1)]
=(π/2). lim(x->∞) [(1+1/e^x)/(1- 1/e^x)]
=π/2
解:x→+∞,arctanx→π/2,e^-x→0,(e^x+1)/(e^x-1)=(1+e^-x)/(1-e^-x)→1
原式极限为π/2
x→-∞,arctanx→-π/2,e^x→0,(e^x+1)/(e^x-1)=→-1
原式极限为π/2
综上,lim[x→∞] (e^x+1)/(e^x-1)arctanx→π/2