Variation
The Delta-variation is a variation in which the varied path over which an integral is evaluated may end at different times than the correct path, and there may be variation in the coordinates at the endpoints.
The delta-variation is a variation in which the varied path in configuration space terminates at the endpoints representing the system configuration at the same time t_1 and t_2 as the correct path; i.e., the varied path always returns to the same endpoints in configuration space, so
| deltaq_i(t_1)=deltaq_i(t_2)=0. |
See also
Calculus of Variations, Euler-Lagrange Differential Equation, Euler-Lagrange Derivative, Functional Derivative, Variation of Argument, Variation of ParametersExplore with Wolfram|Alpha
WolframAlpha
More things to try:
Cite this as:
Weisstein, Eric W. "Variation." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Variation.html