Question

jup mk na??

cho a,b,c>0va a+b+c<+1.c/m

1/(1+a)+1/1+b+1/1+c>=2

Answer 1

Áp dụng Bđt \(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}\ge\frac{9}{a+b+c}\)ta có:

\(\frac{1}{1+a}+\frac{1}{1+b}+\frac{1}{1+c}\ge\frac{9}{1+a+1+b+1+c}\)\(=\frac{9}{4}\ne2\)

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