Question

Cho \(S=\frac{1}{5}+\frac{1}{5^2}+\frac{1}{5^3}+...+\frac{1}{5^8}\)so sánh S với 1

Answer 1

S=1/5+1/5²+1/5³+...+1/5⁸

5S=1+1/5+1/5²+...+1/5⁷

4S=1-1/5⁸<1

\(\Rightarrow\)S<1

gium nha

Answer 2

S=1/5+1/5²+1/5³+...+1/5⁸

5S=1+1/5+1/5²+...+1/5⁷

4S=1-1/5⁸<1

=> S<1

Answer 3

S=1/5+1/5²+1/5³+...+1/5⁸

5S=1+1/5+1/5²+...+1/5⁷

4S=1-1/5⁸<1

=> S<1

Đáp số: đpcm