19/11/07 08:38:37.89 3snBEz3A.net
>>37 より
a_{k+1} -1 = a_k (a_k -1),
1/a_k ＝ 1/(a_k -1) - 1/(a_{k+1} -1),
Σ[k=1,n] 1/a_k = 1/(a_1 -1) - 1/(a_{n+1} -1),
>>42 と同じだが。
19/11/07 08:38:37.89 3snBEz3A.net
>>37 より
a_{k+1} -1 = a_k (a_k -1),
1/a_k ＝ 1/(a_k -1) - 1/(a_{k+1} -1),
Σ[k=1,n] 1/a_k = 1/(a_1 -1) - 1/(a_{n+1} -1),
>>42 と同じだが。