Solution

ID: past-exam-of-the-mathematics-course-of-the-year-2-of-the-natural-sciences-course-of-the-university-of-cambridge/2024/paper-1/9/a/solution

For fixed initial and final coordinates, the two Euler-Lagrange equations are
Indeed the first variation of the functional is
Integration by parts moves the time derivatives from the variations; their endpoint values are zero. The fundamental lemma of the calculus of variations then gives the two equations above.

New to topics? Read the docs here!