Classical Mechanics (Kibble & Berkshire) · Problem 13.3
Hamilton's equations and phase space — T.W.B. Kibble, F.H. Berkshire
Physics — Mechanics · euler-lagrange-equation
Problem
Find the extremal of the path length functional
L[y]=∫01[1+(dxdy)2]1/2dx
that satisfies y(0)=y(1)=0 and show that it does provide the global minimum for L.