C(n,3)=n!/[(n-3)!* 3!]
=(n-2)*(n-1)*n/6
C(n,3)/(n^3 + 1)=(n-2)*(n-1)*n/[6*(n^3 + 1)]
因为lim[6*(n^3 + 1)]= 6 ≠ 0
所以 lim{(n-2)*(n-1)*n/[6*(n^3 + 1)]}
= lim[(n-2)*(n-1)*n]/lim[6*(n^3 + 1)]
=0/6
=0
C(n,3)=n!/[(n-3)!* 3!]
=(n-2)*(n-1)*n/6
C(n,3)/(n^3 + 1)=(n-2)*(n-1)*n/[6*(n^3 + 1)]
因为lim[6*(n^3 + 1)]= 6 ≠ 0
所以 lim{(n-2)*(n-1)*n/[6*(n^3 + 1)]}
= lim[(n-2)*(n-1)*n]/lim[6*(n^3 + 1)]
=0/6
=0