數學名義變數問題..

Sum of (k -1)^3 from k = 1 to k = n is equivalent to sum of k^3 from k = 1 to k = (n-1). So their difference = n^3.

2008-09-23 10:16:05 補充：
That is (1^3 + 2^3 + 3^3 +.......+ (n-1)^3 + n^3) - [ 0^3 + 1^3 + 2^3 + ......+ (n-1)^3] = n^3.