1. The problem statement, all variables and given/known data x(d^2y/dx^2)+dx/dt+xy=0 2. Relevant equations 3. The attempt at a solution At first I thought it was an ODE, but then I found out the derivative was respect to to variables x and t. I am not sure if it is an ODE or PDE. What are the dependent and independent variables in the equation? Is it linear?