09/02/21 03:25:55
〔問題〕
n は自然数, N = 3n(2n^2 +1) のとき
{N + (n^2)/N}^2 < (2n＾2 +1)(3n^2 +1)(6n^2 +1) < {N + 1/(6n)}^2,
(略証)
・左側
(左辺) = N^2 + 2n^2 + {(n^2)/N}^2 < N^2 +2n^2 +1 = N{N + 1/(3n)} = (中辺),
・右側
(中辺) = N{N +1/(3n)} < ｛N +1/(6n)}^2,
ｽﾚﾘﾝｸ(math板:555番)
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