0720132人目の素数さん
2018/05/09(水) 22:47:37.98ID:GEUtkttza_n /(n-1)! = b_n とおくと
b_0 = a_0
b_{n+1} = b_n + 2/n!
= b_0 + Σ[k=0,n] 2/k!
→ a_0 + 2 e (n→∞)
>>716 >>718
a_n /(n-1)! = b_n とおくと
b_1 = a_1
b_{n+1} = b_n + 2/(n・n!)
= b_1 + Σ[k=1,n] 2/(k・k!)
→ b_1 + ∫[0,1] 2(e^x - 1)/x dx
= a_1 + 2{Ei(1) - γ}
= a_1 + 2・1.317902154544 (n→∞)