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a>b>c>0求证:a^a*b^b*c^c>(abc)^((a+b+C)/3)

2012-05-04 来源:年旅网

有网友碰到这样的问题“a>b>c>0求证:a^a*b^b*c^c>(abc)^((a+b+C)/3)”。小编为您整理了以下解决方案,希望对您有帮助:

解决方案1:

对左边取对数:

lg(a^ab^bc^c)=alga+blgb+clgc

a>b>c>0
alga+blgb+clgc>algb+blgc+clga
alga+blgb+clgc>algc+blga+clgb
alga+blgb+clgc=alga+blgb+clgc

上面三式相加:
3lg(a^ab^bc^c)
=3(alga+blgb+clgc)
=(algb+blgc+clga)+(algc+blga+clgb)+(alga+blgb+clgc)
=(a+b+c)(lga+lgb+lgc)
=lg(abc)^{a+b+c}

即a^a*b^b*c^c>(abc)^((a+b+C)/3)

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