17/07/15 03:52:45.75 jZ3tY0g5.net
>>69
[第6章.908]
s = a+b+c, t = ab+bc+ca, u = abc とおく。
st = (aaa+bbb+ccc)＋(abb+bcc+caa)＋(aab+bbc+cca) = S+p+q ≧ 3(Spq)^(1/3),
pq = T+uS+3uu ≧ 3(3STU)^(1/3) ≧ 3√(3SU),
∴ S+p+q ≧ 3(Spq)^(1/3) ≧ 3√(3Su),
ここに、S=aaa+bbb+ccc、T=(ab)^3+(bc)^3+(ca)^3、U=(abc)^3.
Casphy!-不等式2-177