I'm using the method of undetermined coefficients here, but I'm either not making the correct ansatz or I'm just confused on the method. The problem is 2y'' + 3y' + y = t^2. I gussed Y = At^2. Is this correct? It doesn't solve the differential equation, which is the only check I know. So from there (assuming Y is correct) I plug in and get 4A +6At + At^2 = t^2. Now I don't know what to do next.