Find all pairs of positive real numbers (a, b) such that \frac{n-2}{a} \leq \lfloor bn \rfloor < \frac{n-1}{a} for all positive integers n.
Find all pairs of positive real numbers (a, b) such that \frac{n-2}{a} \leq \lfloor bn \rfloor < \frac{n-1}{a} for all positive integers n.