19/10/13 19:01:39.86 m8dyiQfg.net
>>746
amgmだけで
a = (a+b+c+d)/4 ≧ (abcd)^(1/4) = d
b = ((ab + ac+ ad + bc + bd + cd)/6)^(1/2)
≧ ((abacadbcbdcd)^(1/6))^(1/2) = (abcd)^(1/4) = d
c = ((abc + abd+ acd + bcd)/4)^(1/3)
≧ ((abcabdacdbcd)^(1/4))^(1/3) = (abcd)^(1/4) = d