Differential Equations

If \(y{{dy} \over {dx}} = x\left[ {{{{y^2}} \over {{x^2}}} + {{\phi \left( {{{{y^2}} \over {{x^2}}}} \right)} \over {\phi '\left( {{{{y^2}} \over {{x^2}}}} \right)}}} \right]\), x > 0, \(\phi\) > 0, and y(1) = \(-\)1, then \(\phi \left( {{{{y^2}} \over 4}} \right)\) is equal to :