Select all the correct statements below. The eigenfunctions Un (a ) of a Regular Sturm-Liouville System corresponding to an eigenvalue An, for a fixed 72, are unique except for a multiplicative constant. O Any continuous function defined on an closed interval can be expanded as an infinite linear combination of eigenfunctions of a Regular Sturm-Liouville System defined on that same closed interval. Eigenfunctions of a Regular Sturm-Liouville System corresponding to different eigenvalues are orthogonal. All eigenvalues of a Regular Sturm-Liouville problem are strictly positive. The eigenvalues of a Regular Sturm-Liouville System sometimes can have two linearly independent eigenfunctions. All eigenvalues of a Regular Sturm-Liouville System are complex-valued with non- zero real part. All eigenvalues of a Regular Sturm-Liouville System are complex-valued with zero real part. All eigenfunctions of a regular Sturm-Liouville System are unit functions. The problem y"(x) dy(x), y'(0) 1, y' (1) = 2, is not a Regular Sturm-Liouville System. The problem y" (x) + 2y'(x) +y(x) = >y(x), y'(0) = 0, y(1) = 0, is a Regular Sturm-Liouville System. All eigenvalues of a Regular Sturm-Liouville System are real-valued