close
標題:
sequence 希望有高手能回答
發問:
Given the sequence A (n) : 2, 5, 10, 17, 26, 37, 50, ..., find the general term A (n) and the sum S (n) of the firstn terms A n = S n =
最佳解答:
Given the sequence A (n) : 2, 5, 10, 17, 26, 37, 50, ..., find the general term A (n) and the sum S (n) of the first n terms A1 = 1 + 12 A2 = 1 + 22 A3 = 1 + 32 A4 = 1 + 42 A5 = 1 + 52 A6 = 1 + 62 A7 = 1 + 72 An = 1 + n2 Sn = n + ∑n2 = n + n(n+1)(2n+1)/6 = n[1 + (n+1)(2n+1)/6] = n(2n2 +3n +7)/6
其他解答:
此文章來自奇摩知識+如有不便請留言告知
文章標籤
全站熱搜
留言列表
