3. Find the extrema (local maxima or minima) of the following
functions or functionals.
申論題內容
(4)(申論題10%)Obtain the differential equation of f(x)that achieves extremum of a functional I[If(●)]=dx. Here we have a boundary conditions given by f(a) = fa, f(b) = fb, f'(a)=f'a, f'(b)=f'b.