Chapter 4.P4, Problem 6P

Carry out the calculations that lead from Eq. to Eq. in the discussion preceding Problem .

where the perturbation vector satisfies

and

Thus, for defined by Eq. , we compute , integrate by parts, and use the endpoint conditions to arrive at

Since Eq. must hold for any and satisfying the conditions , we conclude that each factor multiplying and in the integrand must equal zero,