If a curve y=f(x), passing through the point (1,2), is the solution of the differential equation, 2 x^2 d y=(2 x y+y^2) d x, then f(1/2) is equal to:

If a curve $\displaystyle y=f(x)$, passing through the point $\displaystyle (1,2)$, is the solution of the differential equation, $\displaystyle 2 x^2 \mathrm{~d} y=\left(2 x y+y^2\right) \mathrm{d} x$, then $\displaystyle f\left(\frac{1}{2}\right)$ is equal to :