\[
(f+g)(x) = \sqrt{2x - 1} + \frac{1}{x} \quad \text{with domain} \quad \boxed{[\frac{1}{2}, \infty)}
\]
\[
(f-g)(x) = \sqrt{2x - 1} - \frac{1}{x} \quad \text{with domain} \quad \boxed{[\frac{1}{2}, \infty)}
\]
\[
(fg)(x) = \frac{\sqrt{2x - 1}}{x} \quad \text{with domain} \quad \boxed{[\frac{1}{2}, \infty)}
\]
\[
\left(\frac{f}{g}\right)(x) = x \sqrt{2x - 1} \quad \text{with domain} \quad \boxed{[\frac{1}{2}, \infty)}
\]