求极限:lim(n→∞)[n-(√n*2+n)+1].
n-√(n^2+n)+1=(n-√(n^2+n))(n+√(n^2+n))/(n+√(n^2+n))+1
=(n^2-(n^2+n))/(n+√(n^2+n))+1
=-n/(n+√(n^2+n))+1
=1-1/(1+√(1+1/n))
所以:lim(n→∞)[n-√(n^2+n)+1]= lim(n→∞)[1-1/(1+√(1+1/n))]
=1-1/2
=1/2
求极限:lim(n→∞)[n-(√n*2+n)+1].
n-√(n^2+n)+1=(n-√(n^2+n))(n+√(n^2+n))/(n+√(n^2+n))+1
=(n^2-(n^2+n))/(n+√(n^2+n))+1
=-n/(n+√(n^2+n))+1
=1-1/(1+√(1+1/n))
所以:lim(n→∞)[n-√(n^2+n)+1]= lim(n→∞)[1-1/(1+√(1+1/n))]
=1-1/2
=1/2