The value of \( \cot^{-1}\!\left(\dfrac{\sqrt{1+\tan^{2}(2)}-1}{\tan(2)}\right) - \cot^{-1}\!\left(\dfrac{\sqrt{1+\tan^{2}\!\left(\dfrac{1}{2}\right)}+1}{\tan\!\left(\dfrac{1}{2}\right)}\right) \) is equal to:
\( \pi + \dfrac{5}{2} \)
\( \pi - \dfrac{5}{4} \)
\( \pi + \dfrac{3}{2} \)
\( \pi - \dfrac{3}{2} \)