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:

aa.jpg

 

此文章來自奇摩知識+如有不便請留言告知

arrow
arrow

    wszspj2 發表在 痞客邦 留言(0) 人氣()