有个公式1^3+2^3+3^3+...+n^3=[(1+n)n/2]^2代入100[(100+1)*100/2]^2=5050^2=25 502 500证明1^3+2^3+3^3+...+n^3=(1+2+3+...+n)^2=[n(n+1)/2]^2 n^4-(n-1)^4 =[n^2-(n-1)^2][n^2+(n-1)^2] =(2n-1)(2n^2-2n+1) =4n^3-...