设a,b,c为正实数,求证1/a^3+ 1/b^3+ 1/c^3+ abc>=2根号3

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设a,b,c为正实数,求证1/a^3+ 1/b^3+ 1/c^3+ abc>=2根号3

设a,b,c为正实数,求证1/a^3+ 1/b^3+ 1/c^3+ abc>=2根号3
设a,b,c为正实数,求证1/a^3+ 1/b^3+ 1/c^3+ abc>=2根号3

设a,b,c为正实数,求证1/a^3+ 1/b^3+ 1/c^3+ abc>=2根号3
a>0,b>0,c>0,abc>0 1/a^3+ 1/b^3+ 1/c^3≥3 三次根号下1/a^3b^3c^3=3/abc 3/abc+abc≥2√(3/abc*abc)=2√3 故1/a^3+ 1/b^3+ 1/c^3+abc≥2√3