arithmetic sequences我只系學過
(1,3,5,7,9)
(1+9)/2 ,頭+尾除2等於中間果個數
但如果只比頭同尾 1 , ___ , ____ , 7
咁應該要點計第2個同第3個數?
咁如果1 , ___ , ____ , _____ , ______ ,11
咁又要點計?
thx~
arithmetic sequences問題
2012-10-11 2:17 am
回答 (2)
2012-10-19 1:24 am
✔ 最佳答案
in arithmetic sequences, general formula for a nth term, T(n) = a + (n-1)dwhere
a = first term = T(1)
d = common difference = T(n) - T(n-1)
n = number of terms in sequence
from your last question,
sequence: T(1)=1, T(2), T(3), T(4), T(5), T(6)=11
T(1) = 1 and T(6) = 11
thus, T(6) = T(1) + (6-1)d
11 = 1 + (6-1)d
=> d = 2
thus, T(2) = T(1) + (2-1)d = 3
thus, T(3) = T(1) + (3-1)d = 5
etc...
2012-10-11 11:21 pm
1 + (1/3)(7 - 1) = 3
1 + (2/3)(7 - 1) = 5
1 + (1/5)(11 - 1) = 3
1 + (2/5)(11 - 1) = 5
1 + (3/5)(11 - 1) = 7
1 + (4/5)(11 - 1) = 9
1 + (2/3)(7 - 1) = 5
1 + (1/5)(11 - 1) = 3
1 + (2/5)(11 - 1) = 5
1 + (3/5)(11 - 1) = 7
1 + (4/5)(11 - 1) = 9
參考: knowledge
收錄日期: 2021-04-28 14:21:10
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https://hk.answers.yahoo.com/question/index?qid=20121010000051KK00389