0827132人目の素数さん
2018/11/19(月) 11:18:44.31ID:eL1RQpps面白スレの解答は…
f(x) = (x^2 +2ax+b)(x^2 +2cx+d) = x^4 -(8/3)x^3 -2x^2 +8x+1,
(a^2 -b)(c^2 -d) = (7/6 -f/2)^2 -(20/27)^2/(7/6 +f/2)
= (1/3)[10 - (13+2√11)^{2/3} - (13-2√11)^{2/3}]
= -0.2376189664261441
< 0,
面白スレ28-319,321