Let \( f(x)=\int \dfrac{2x}{(x^{2}+1)(x^{2}+3)}\,dx \). If \( f(3)=\dfrac{1}{2}\big(\log_{e}5-\log_{e}6\big) \), then \( f(4) \) is equal to:
\( \log_{e}17-\log_{e}18 \)
\( \dfrac{1}{2}\big(\log_{e}19-\log_{e}17\big) \)
\( \dfrac{1}{2}\big(\log_{e}17-\log_{e}19\big) \)
\( \log_{e}19-\log_{e}20 \)