Hi all, I am trying to implement the backward euler integration (in c++) for the pendulum problem. I have the forward euler implemented, but frankly I don't know where to even start from for the implicit integration. I understand the update expressions for implicit, and of course the pendulum motion (theta'' = -gravity / length * sin (theta) ). Almost all content online explaining implicit integration give the update expressions and say that you have to solve for x (t+1), but I haven't found any resources that actually explain how to solve them. I am not looking for libraries that do this already, I would like to learn the process and do it myself (except maybe for matrix inversion etc). If you understand the process of solving for x(t+1) would you please enlighten me? Do I need to find the derivative of the acceleration? Do I need to write the motion function ( -gravity / length * sin (theta) ) in matrix notation? Very confused. Thank you so much!