試寫出下列各數列的第 n 項 。
(a) 4, 7, 10,13... (b) 5, 8, 11, 14, ...
(c) 2, 6, 10,14... (d) 10, 17, 24, 31, ....
請幫手
請講埋如何計出答案 謝謝
(a) 3n - 2
(b) 2 + 3n
(c) 4n - 2
(d) 7n+ 3
2006-10-18 22:19:35 補充：
(a) 3n 1(a) 4 = 3 1 7 = 6 1N = 3n 1(b) 5 = 2 3 8 = 2 6N = 2 3n(c) 2 = 4 - 2 6 = 8 - 2N = 4n - 2(d) 10 = 7 3 17 = 14 3N = 7n 3
a) 4 + (n -1) 3 c) 2+ (n -1) 4
= 4 + 3n -3 = 2 + 4n - 4
= 3n -1 = -2 +4n
= 4n -2
b) 5 +(n -1 ) 3 d) 10+ (n- 1) 7
= 5+ 3n - 3 = 10+7n -7
= 2 +3n = 3+ 7n
Copyright © 2024 1QUIZZ.COM - All rights reserved.
Answers & Comments
Verified answer
(a) 3n - 2
(b) 2 + 3n
(c) 4n - 2
(d) 7n+ 3
2006-10-18 22:19:35 補充：
(a) 3n 1(a) 4 = 3 1 7 = 6 1N = 3n 1(b) 5 = 2 3 8 = 2 6N = 2 3n(c) 2 = 4 - 2 6 = 8 - 2N = 4n - 2(d) 10 = 7 3 17 = 14 3N = 7n 3
a) 4 + (n -1) 3 c) 2+ (n -1) 4
= 4 + 3n -3 = 2 + 4n - 4
= 3n -1 = -2 +4n
= 4n -2
b) 5 +(n -1 ) 3 d) 10+ (n- 1) 7
= 5+ 3n - 3 = 10+7n -7
= 2 +3n = 3+ 7n