Question
If n \in N^+ , prove
\dfrac{1}{2}\leq\dfrac{1}{n+1}+\dfrac{1}{n+2}+\dots+\dfrac{1}{2n}<1
If n \in N^+ , prove
\dfrac{1}{2}\leq\dfrac{1}{n+1}+\dfrac{1}{n+2}+\dots+\dfrac{1}{2n}<1
\because n < n+k <2n
\therefore \dfrac{1}{2n} <\dfrac{1}{n+k}<\dfrac{1}{n}