要步驟!!
5^n+3-5^n+1
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3．5^n
一題數學(10分)
2006-10-22 8:59 pm
回答 (1)
2006-10-22 9:07 pm
✔ 最佳答案
[5^(n + 3) - 5^(n + 1)] / [3 * (5^n)]= [5^n * 5^3 - 5^n * 5^1] / [3 * (5^n)]
= [125 * (5^n) - 5 * (5^n)] / [3 * (5^n)]
= [120 * (5^n)] / [3 * (5^n)]
= 120 / 3
= 40
收錄日期: 2021-04-23 15:48:01
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061022000051KK02081