因为1/a 1/b≥2√(1/ab)=2√c,同理1/c 1/b≥2√(1/cb)=2√a,1/a 1/c≥2√(1/ac)=2√b,三式相加得1/a 1/b 1/c≥√a √b √c因为a,b,c互不相等,所以1/a 1/b 1/c>√a √b √c
