1. The problem statement, all variables and given/known data Let a particle of mass m moving in 2d space in a potential V (x, y) = -1/2 kx2 + 1/2 λ0 x2y2 + 1/4λ1x where k,λ0,λ1 > 0.At what point (x0, y0) is the particle in stable equilibrium? 2 marks 2. Relevant equations ∂V/∂x=0 ∂V/∂y=0; ∂2V/∂x2 > 0;∂2V/ ∂y2 > 0 3. The attempt at a solution After using relevant equations I get x= λ1/4 (k-y2 λ0) and λ0 x2 y =0. If I take x or y=0 then the point become unstable. Don't know what to do next.The problem however simplifies very much for a 2 mark question if the first term of the potential right side is positive.Does anybody think that it could be a typo error? Or is this problem solvable in the given form? If the first term were to be positive then stable point would be (λ1 /4k , 0) .This would satisfy all the conditions.