Jēkabpilī viltus sociālās darbinieces nozog sirmgalvim 2500 latus

You're on top of the game. Thanks for sahring.

I'd never seen a derivation, which is why mine is so lcunky.My thinking was: write down F=MA and go from there. Knowing that the end result is an ellipse means that the solution can be in a form that's independent of time (it's just a shape). I chose to used R and theta instead of x and y because the conservation of momentum has a simpler form, and it gives you a chance to get rid of the time dependence.Also, this was my third or fourth attempt. The first ones were tumbling train wrecks. The derivations you see are almost never the first attempt, and generally it's streamlined so much that you can barely see what the author was thinking.In your first year it would be unusual to be able to do this. Having experience seeing tricks other people use is in derivations is very important. When a professor is deriving stuff it helps (both of you) to ask why did you do that? or what is the goal in this step? . Harass them during office hours as often as you can, and keep a dialog open while they work through problems. It takes the mystery away from the whole process.