结论是对的.因1^3+2^3+...+n^3=[n*(n+1)/2]^2 (可由数学归纳法证明),因此
(1/N)^3+(2/N)^3+……+(N/N)^3=[n*(n+1)/2]^2/n^3= 1/4 *(n^4+2n^3+n^2)/n^3= (1/4*n^2+1/2*n+1/4)/n,即取A=1/4,B=1/2,C=1/4即可.