>>909
〔Jacobsthalの不等式〕

 (n+1)(A-G) ≧ n(Ao - Go),

(略証)
(左辺)= (n・Ao +x) -(n+1)(Go^n・x)^{1/(n+1)}
 ≧(n・Ao +x) - (n・Go +x)
 = n(Ao - Go)
 =(右辺),