If you could write the Euler-Lagrange equation on the board during the test it'd be awesome. I imagine a lot of us will forget it on our post-it notes.
Is there a good way to think conceptually of what a Lagrangian represents? Without explaining it in too much math, why is it K-U? I can see what the Lagrangian is in terms of the equations, but I don't have an intuitive idea about it.
Ah the correct slide, a proof is given here (in like first 12 pages) for Euler-Lagrangian equation.
refrence : 16-811 Math Funda for Robotics CMU
@Sohil It is just another way of writing Force=Mass*Acceleration.
I think the reason it exists is because now we just have a bunch of derivatives on a single quantity, so we can solve problems with our differential equations toolbox.
Really understanding this stuff takes a bit more work; you might want to start with the Wikipedia page for Lagrangian mechanics.