c/2a+c/2b=c*(a+b)/2ab=2c*(a+b)/4ab>=2c*(a+b)/(a+b)^2=2c/(a+b)
同理b/2a+b/2c>=2b/(a+c),a/2b+a/2c>=2a/(b+c)
三式相加得(a+b)/2c+(b+c)/2a+(a+c)/2b>=2c/(a+b)+2a/(b+c)+2b/(a+c)
(a+b)^2>=4ab知道吗?
c/2a+c/2b=c*(a+b)/2ab=2c*(a+b)/4ab>=2c*(a+b)/(a+b)^2=2c/(a+b)
同理b/2a+b/2c>=2b/(a+c),a/2b+a/2c>=2a/(b+c)
三式相加得(a+b)/2c+(b+c)/2a+(a+c)/2b>=2c/(a+b)+2a/(b+c)+2b/(a+c)
(a+b)^2>=4ab知道吗?