1. The problem statement, all variables and given/known data Please help me solve this differential equation: This is mass attached to a spring, we have F= ma= -kx -bv + Fext where k and v are spring constant and velocity respectively and Fext is an additional external force. 2. Relevant equations I know how to solve nonhomogeneous differential equations mathematically but on the right of the above equation is not a function so I stuck. 3. The attempt at a solution I tried this way: writing the above as differential equation I have md2x/dt2 + bdx/dt + kx = Fext for homogeneous part md2x/dt2 + bdx/dt + kx=0 the solution I assumed is x(t) =Aept the first derivative of the assumed solution is x'(t)= Apept and the second derivative is x''(t)= Ap2ept substituting all these x(t), x'(t) and x''(t) to the differential equation and devide by Aept I get: mp2 + bp+k=0 for inhomogeneous part I don't know ho to handle this right hand side Fext. Please help me.