Suppose A is a symmetric matrix with positive eigenvalues, the smallest of which is 2 and the largest of which is 2. Suppose we wish to approximately solve the system Ar = b through iteration without knowing the true solution x*, and our approximation at the hth iteration is z(). Suppose ||b||2 = 4. If we wish the relative error w.r.t. the 2-norm to be less than 10-, what should we use as a stopping condition involving the residual error, and why?
