假设a,b,c是正实数.a^2 + b^2 + c^2 + (a + b + c)^2 ≤ 4.请证明3≤ [(ab+1)/(a+b)^2]+[(bc+1)/(b+c)^2]+[(ca+1)/(c+a)^2]

假设a,b,c是正实数.a^2 + b^2 + c^2 + (a + b + c)^2 ≤ 4.请证明3≤ [(ab+1)/(a+b)^2]+[(bc+1)/(b+c)^2]+[(ca+1)/(c+a)^2]
假设a,b,c是正实数.a^2 + b^2 + c^2 + (a + b + c)^2 ≤ 4.请证明
3≤ [(ab+1)/(a+b)^2]+[(bc+1)/(b+c)^2]+[(ca+1)/(c+a)^2]

假设a,b,c是正实数.a^2 + b^2 + c^2 + (a + b + c)^2 ≤ 4.请证明3≤ [(ab+1)/(a+b)^2]+[(bc+1)/(b+c)^2]+[(ca+1)/(c+a)^2]
额,难啊

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