$ \text{Let } y=y(x) \text{ be the solution curve of the differential equation } \dfrac{dy}{dx}+\dfrac{1}{x^{2}-1},y=\left(\dfrac{x-1}{x+1}\right)^{1/2},; x>1,\ \text{passing through the point } \left(2,\sqrt{\tfrac{1}{3}}\right). \text{ Then } \sqrt{7},y(8) \text{ is equal to:} $