4. 0 Let y" = f(r) where f : R Q.7 equation R be the solution of the following differential (2y sin r+3y sin z cos r)dr - (4y cos +cos r)dy = 0; which passes through the origin then 1. flz) is bounded 2. f(r) is unbounded 3. flr) is injective 4. f(r) is surjective