\[\boxed{\mathbf{1285}\mathbf{.}}\]
\[= \frac{a^{2} + 2ab + b^{2}}{4ab} = \frac{(a + b)^{2}}{4ab};\]
\[= \frac{\left( \sqrt{a} + \sqrt{b} \right)^{2}}{ab \bullet \left( \sqrt{a} + \sqrt{b} \right)^{2}} = \frac{1}{\text{ab}}.\]