Bđt

E

eye_smile

$1-a=b+c \ge 2\sqrt{bc}$

$1-b=a+c \ge 2\sqrt{ac}$

$1-c=a+b \ge 2\sqrt{ab}$

Nhân theo vế \Rightarrow đpcm.
 
P

phamhuy20011801

Ta có: a+b+c=1
\Rightarrow 1-a=b+c; 1-b=a+c; 1-c=a+b
$(1 – a)(1 – b)(1 – c)=(b + c)(a + c)(a + b) \ge 2\sqrt{bc}.2\sqrt{ac}.2\sqrt{ab}= 8abc$
( áp dụng bất đẳng thức Cô si)
 
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