1. The problem statement, all variables and given/known data Find the equations of the trajectories of y"+y^3=0. 2. Relevant equations None. 3. The attempt at a solution y"+p(y)=0 v(dv/dy)+p(y)=0 integrate v^2/2+P(y)=C so I got v^2/2+y^4/4=C. Is v^2/2+y^4/4=C the correct answer?