f(x1x2)的最小值
f(x) =[(log(2)x -1]/[log(2)x +1] =1 -2/[log(2)x +1] 简记:a=log(2)x1, b=log(2)x2 f(x1)+f(2x2)=1 ==> [1 -2/(a+1)]+[1 -2/(b+2)] =1 a =(b+4)/b f(x1*x2) =1 -2/(a+b+1) =1 -2/(2 +b +4/b) >= 2/3 f(x1*x2)最小值 =2/3
答:解: ∵a=x1+x2+x3≥3(x1x2x3)^(1/3)=3a^(1/3) ∴a≥3根3; 而3(x1x2+x2x3+x3x1)≤(x1+x2+x3)^2,...详情>>
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