Ok, I found it. thanks anyways.(http://www.physics.ucla.edu/~cwp/lists/accDB_su.html)
Symmetry is THE most powerful tool in solving differential equations. If you are a young math major you should difinitely think about going to a school where symmetry classes are avaliable.
I am in need of Noether's paper she wrote in around 1915 about variational symmetries.
I need to know how she found that [for an ode L(x,y,y')]if an X and Y (infinitesimals) exists then you can rewrite the Euler-Lagrange Equation in terms of L(x,y,y'), X(x,y) and Y(x,y).
This is really...
I'm currently taking a symmetry analysis course. It is really interesting. I would recommend it to any math major or anyone interested in ODE's and PDE'S. I am enjoying it very much.