The value of the integral \( \displaystyle \int_{1/2}^{2} \frac{\tan^{-1} x}{x} \, dx \) is equal to:
\( \frac{1}{2} \log_{e} 2 \)
\( \frac{\pi}{2} \log_{e} 2 \)
\( \pi \log_{e} 2 \)
\( \frac{\pi}{4} \log_{e} 2 \)