Question

[Lynk Hoàng]

1. Cho S₁=1+\(\frac{1}{5}\)

S₂=1+\(\frac{1}{5}+\frac{1}{5^2}\)

.....

S_n=\(1+\frac{1}{5}+.....\frac{1}{5^n}\)

CMR:\(\frac{1}{5.S_1^2}+\frac{1}{5^2.S_2^2}+....+\frac{1}{5^n.S^2_n}< \frac{1}{4}\)

Answer 1

[Thanh Huyền Army]

https://i.imgur.com/Zvvyc6l.jpg