Câu hỏi 25
Chứng minh rằng
$$
\frac{1}{1999} \lt \frac{1}{2} \cdot \frac{3}{4} \cdot \frac{5}{6} \cdots \frac{1997}{1998} \lt \frac{1}{44}
$$
$$
\frac{1}{1999} \lt \frac{1}{2} \cdot \frac{3}{4} \cdot \frac{5}{6} \cdots \frac{1997}{1998} \lt \frac{1}{44}
$$