3楼: Originally posted by 立迷特 at 2017-07-20 08:24:14
将1+1/a_k变成\frac{a_{k+1}}{(k+1)a_k}, 然后得到乘积为\frac{a_{n+1}}{(n+1)!} 计算得\frac{a_{n+1}}{(n+1)!}=\frac{a_n}{n!}+\frac{1}{n!}=\frac{a_{n-1}}{(n-1}!}+\frac{1}{(n-1)!}+\frac{1}{n!}=\cdots，依次递 ...