CHO A, B, C > 0 2 2 2A B C A B CCMR

Câu 5:

Cho a, b, c > 0

2

2

2

a

b

c

a

b

c

CMR:

2

2

2

2

2

2

b

c

c

a

a

b

b c

c

a

a b