(16 pts) Let f(x) = 21|Ax - bll3 + lla? where A E R10x5, x E R5 and b E R10. (a) Prove Vf(x) is Lipschitz continuous with Lipschitz constant L = | |A" All + 1. (b) Write down the kth iteration of the gradient descent method with stepsize being 7. (c) Write down the kth iteration of Newton's method