Let \( y=y(x) \) be the solution of the differential equation \( \dfrac{dy}{dx}=(1+x+x^{2})(1-y+y^{2}) \), \( y(0)=\dfrac{1}{2} \). Then \( (2y(1)-1) \) is equal to:
\( \sqrt{3}\,\tan\!\left(\dfrac{11\sqrt{3}}{6}\right) \)
\( \dfrac{\sqrt{3}}{2}\,\tan\!\left(\dfrac{11\sqrt{3}}{12}\right) \)
\( \sqrt{3}\,\tan\!\left(\dfrac{11\sqrt{3}}{12}\right) \)
\( \dfrac{\sqrt{3}}{2}\,\tan\!\left(\dfrac{11\sqrt{3}}{6}\right) \)