作者eric80520 (freejustice)
看板Math
标题[微积] 一题高微
时间Sat Apr 9 23:14:59 2011
题目 Suppose that {ak} is a decreasing sequence of real numbers.
∞
Prove that if Σak converges, then kak→0 as k→∞.
k=1
我目前会的
∞
since Σak converges,so ak→0 as k→∞
k=1
by {ak} is decreasing and →0 ,so {ak} is nonegative sequence
再来好像要分2k跟2k+1讨论, 可是我不太清楚要怎麽做
可以教我吗 谢谢
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