If $y=y(x)$ is the solution of the differential equation, $x{dy\over dx}+2y = x^2$ satisfying $y(1) = 1,$ then $y({1\over2})$ is equal to :

(1) $7\over64$

(2) $13\over16$

(3) $49\over16$

(4) $1\over4$

(1) $7\over64$

(2) $13\over16$

(3) $49\over16$

(4) $1\over4$