这两题级数怎么求?能能详细解析下吗?谢谢俶

2025-04-09 06:26:55
推荐回答(1个)
回答1:

∑[an-2a(n+1)]
=∑an-2∑a(n+1)
=S-2(S-a1)
=2a1-S
∑(1/2)^(n-1)

=(1/2)/(1-1/2)
=1