http://sphotos-e.ak.fbcdn.net/hphotos-ak-frc1/904626_452276058194778_638354837_o.jpg
Really in trouble!!
Thanks for helping!
Question about series...?
2013-05-06 4:20 pm
回答 (1)
2013-05-06 5:00 pm
✔ 最佳答案
Using the Ratio Test:r = lim(n→∞) |[(-7)^(n+1)/((5(n+1)+6) 8^(n+3))] / [(-7)^n/((5n+6) 8^(n+2))]|
..= lim(n→∞) |[7^(n+1)/((5n+11) 8^(n+3))] * [(5n+6) 8^(n+2) / 7^n]
..= (7/8) * lim(n→∞) (5n+6)/(5n+11)
..= (7/8) * 1
..= 7/8.
Since r = 7/8 < 1, this series converges absolutely.
I hope this helps!
收錄日期: 2021-05-01 14:47:22
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130506082022AA89LMO