Giải thích các bước giải:
Câu VI:
Áp dụng BDT cosi ta có :
$(\dfrac{a}{b}+\dfrac{1}{2})(\dfrac{b}{c}+\dfrac{1}{2})(\dfrac{c}{a}+\dfrac{1}{2})$
$\ge(2\sqrt{\dfrac{a}{b}.\dfrac{1}{2}})(2\sqrt{\dfrac{b}{c}.\dfrac{1}{2}})(2\sqrt{\dfrac{c}{a}.\dfrac{1}{2}})$
$\ge(8\sqrt{\dfrac{a}{b}.\dfrac{1}{2}.\dfrac{b}{c}.\dfrac{1}{2}.\dfrac{c}{a}.\dfrac{1}{2}})$
$\ge 2\sqrt{2}$
