Fr.: variation annuelle
Generally, the variation of a quantity over a year. In particular the yearly change in the right ascension or declination of a star, produced by the combined effects of the precession of the equinoxes and the proper motion of the star.
calculus of variations
Fr.: calcul des variations
The study of maximum and minimum properties of → definite integrals.
Fr.: variation séculaire
Same as → secular perturbation.
1) General: An instance of changing, or something that changes.
M.E., from O.Fr. variation, from L. variationem (nominative variatio) "difference, change," from variatus, p.p. of variare "to change," → vary.
Varteš, verbal noun from vartidan, → vary.
Of or describing a → variation.
Fr.: principe variationnel
Any of the physical principles that indicate in what way the actual motion of a state of a mechanical system differs from all of its kinematically possible motions or states. Variational principles that express this difference for the motion or state of a system in each given instant of time are called → differential. These principles are equally applicable to both → holonomic and → nonholonomic systems. Variational principles that establish the difference between the actual motion of a system during a finite time interval and all of its kinematically possible motions are said to be → integral. Integral variational principles are valid only for holonomic systems. The main differential variational principles are: the → virtual work principle and → d'Alembert's principle.