Question

Chứng minh rằng : \(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{255}+\frac{1}{256}>5.\)

Answer 1

Đc lém Min đúng lúc tui đang định đăng câu ó

Answer 2

\(Ta\)  \(có\)  \(1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{256}\)

                   \(Vì\)  \(1>\frac{1}{256},\frac{1}{2}>\frac{1}{256},....,\frac{1}{255}>\frac{1}{256},\frac{1}{256}=\frac{1}{256}\)

                 \(\Rightarrow1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{256}>\frac{1}{256}+\frac{1}{256}+...+\frac{1}{256}\)

                  \(=\frac{1}{256}.256=1\)\(< 5\)