A, CHO 0  A, B, C  1 CMR

Câu 4:

a, Cho 0



a, b, c



1

CMR: a

²

+ b

²

+ c

²



1+ a

²

b + b

²

c + c

²

a

b, Cho 0 <a

0

<a

1

< ... < a

1997

  

....

a

a

a

CMR:

⁰

¹

¹⁹⁹⁷

   

< 3

a

a

a

a

2

5

8

1997