I am trying to solve the following problem and am a bit lost so any advice would be welcomed. x'' = 2x' + x = 3cos2t + sin2t My understanding is that I need to find the general solution for the unforced equation and a particular solution of the above equation. When these are added together then I will get my final solution. Using the charateristic equation: m^2 + 2m + 1 = 0 And then the quadratic equation will give me: m = -1 This gives a general solution of: x(t) = Ae^m0t + Bte^m0t so Ae^-1t + Bte^-1t + particular solution = final answer Is a particular solution x(t) = p cos βt + q sin βt....??? Not really sure where to go from here.