1≤√(1+1/n)≤1+1/(2n)【右边说明：[1+1/(2n)]²=1+1/n+1/(4n²)＞1+1/n】∵lim(n→∞)1=1lim(n→∞)[1+1/(2n)]=1∴lim(n→∞)√(1+1/n)=1
