你好!(b+d))≧(a/(b+d);d≧(a+c)^2/(b+d)=1;b+c^2/根d*根号(d/根b*根(b/(b+d))+c/,所以a^2/(b+d)))^2=(a+c)^2/(b+d)+d/(b+d)而b/(b+d)+d/根据Cauchy不等式(a^2/b+c^2/d)(b/打字不易,采纳哦!