3. Find all functions y(x) which maximise or minimise the functional J[u] = { [-22y+ (0*)] dar with the boundary conditions 7(0) = v(0) = 0, y(t) = 5v (1) = Note: this is a functional of the form J[y] = | F(x, y, y'. y'') dx; it contains y". a higher- order derivative of the function y(r). The method of finding maxima and minima of such functionals is similar to the method of solving the simplest variational problem with fixed ends for functionals of the form J [y] = S F(x,y,y) da, except the Euler-Lagrange equation has to be replaced by the Euler-Poisson equation by < (67)+ CF) - O dy dal You have to solve this equation with the given boundary conditions and analyse what type of an extremum the solution is, if it is an extremum