@solveforx I hate certain derivations, too. It’s ok to dislike them, but you will have to deal with them. They build on each other. Take fluid mechanics, I had a strong grasp on Reynolds Transport Theorem, I had no problem transitioning into linear momentum, Euler’s equations or Navier-Stokes equations. To use the example I provided earlier, if you understand the deviations, get it out the way, you’ll have no problem using the equation and moving on to the next problem.
I’ve seen a lot of people stress over derivations and not understanding them the first time they use them and then they don’t move on to the problems. Don’t do that. Don’t explode your brain. Learn by doing problems and having experience with the equations if you need to.