Q. Identify the following differential equations at first and then find the solutions of them. 1 . (D2 - 4D + 3) y = 2 ex cos 2x, where D =- dx 2 (D2 + 9) y = x2 cos 3x, where D = dx 3. (x3D3 + 3x2 D2 + xD + 1) y = x2 + 2 Inx, where D= dx