Calculus of Variations

Basics of Calculus of variations are discussed in this video, including:
functionals: 0:12
Function's vicinity and functional extrema definition: 9:45
Euler-Lagrange Equation: 18:05
Example 1, shortest curve between two fixed points in a plane: 21:10
Example 2, Equation of motion for a mass-spring system using the Lagrangian and the Action Integral: 24:46
Sufficient conditions for the minimum of a functional: 32:28
First and Second variations of a functional: 34:29