0552132人目の素数さん垢版 | 大砲2019/06/15(土) 19:46:49.33ID:d+NNwnLK >>541 AB = 2a, CD = 2b, a ≧ b > 0, とおくと K = 4a∫[0,π/2] √{1 -(k・sinφ)^2}dφ = 4a E(k), k=√(1-bb/aa), L = 2πa, M = 2πb, K ≧ π(a+b) = (L+M)/2.