6.9. Let f: R R be given by f(x) = x Axxb+c, where A is an n x n symmetric positive definite matrix, b is an n-vector, and c is a scalar. (a) Show that Newton's method for minimizing this function converges in one iteration from any starting point xo. (b) If the steepest descent method is used on this problem, what happens if the starting value xo is such that ox* is an eigenvector of A, where x* is the solution?