1. Write a function M-file to solve min f(x) 1 by the exact gradient descent method, where f(2)= TAc and A is one of the following SPD matrices [92] 21 8 41 18] 2 6 8 9 18 14 (This is a strictly convex problem, the minimizer is r* = 0 and the minimum is 0.) The first line of your M-file should read function (x,min, err,iter] = Exact Gradient_ (x0, tol,N,A) The sub-functions that compute the gradient descent direction and f(x + a) are as follows. function p=GD (x) p=-A*x; end function y=f(x,p, alpha) z=x+alpha*p; y=.5*Z' *A*Z; end Use the initial guess 2) x0= and set N to be 200 and the tolerance to be 10-10 in your computations. Create a diary (HW3Diary-) that records your computations. You diary should contain the results for all three choices of A. (You will get bonus points by including in the diary some brief comments on what you have observed.) Email your M-file and diary as separate attachments