Lim [x^2/(x^2-1)]^x (x→∞)
问题描述:
Lim [x^2/(x^2-1)]^x (x→∞)
答
lim [x^2/(x^2-1)]^x (x→∞) =lim1/[(1-x^(-2))^x]=lim1/[(1-1/x)^x*(1+1/x)^x]=lim1/[(1-1/x)^x]*lim1/[(1+1/x)^x]=1/lim[(1-1/x)^x]*1/lim[(1+1/x)^x]=1/e^(-1)*1/e^1=1前面的lim1怎么出来的呀!你分解的我有点看不懂。不是lim1,我指的是lim(1/[(1-x^(-2))^x]),少打了括号,就是把分子分母同除以x^2你能重新写一遍过程吗?我刚刚学这个。lim [x^2/(x^2-1)]^x (x→∞) =lim(1/[(1-x^(-2))^x])=lim(1/[(1-1/x)^x*(1+1/x)^x])=lim(1/[(1-1/x)^x])*lim(1/[(1+1/x)^x])=(1/lim[(1-1/x)^x])*(1/lim[(1+1/x)^x])=1/e^(-1)*1/e^1 (这里用到了一个常见的极限lim(1+1/x)^x=e(x→∞))=1