Calculus of variations - Wikipedia
https://en.wikipedia.org/wiki/Calculus_of_variationsFinding the extrema of functionals is similar to finding the maxima and minima of functions. The maxima and minima of a function may be located by finding the points where its derivative vanishes (i.e., is equal to zero). The extrema of functionals may be obtained by finding functions where the functional derivative is equal to zero. This leads to solving the associated Euler–Lagrange equation.
Calculus of variations. Functionals. Euler’s equation ...
solitaryroad.com › c500Euler’s equation for integrals involving several functions. The simplest integral in the Calculus of Variations. involves a single function y = f(x). In applications these integrals arise in cases involving only a single functional dependence. An example of a single functional dependence is a curve in the plane defined by y = f(x).
7.2 Calculus of Variations - MIT Mathematics
math.mit.edu › classes › 187.2. CALCULUS OF VARIATIONS c 2006 Gilbert Strang constant: the Euler-Lagrange equation (2) is d dx @F @u0 = d dx u0 p 1+(u0)2 = 0 or u0 p 1+(u0)2 = c: (4) That integration is always possible when F depends only on u0 (@F=@u = 0). It leaves the equation @F=@u0 = c. Squaring both sides, u is seen to be linear: (u0) 2= c (1+(u0)2) and u0 = c p 1 c2 and u = c p 1 c2 x+d: (5)