用夹逼定理计算极限lim{(n^2+1)/(n^4+2*n-1)}

问题描述:

用夹逼定理计算极限lim{(n^2+1)/(n^4+2*n-1)}

Xn=0
Yn=(n^2+1)/(n^4+2*n-1)
Zn=(n^2+1)/(n^4-1)=1/(n^2-1)
Xn