Optimization compute gradient

  1. (20 pts) Denote ei as the ith column of the identity matrix In E lr" for i = Let 1(x) = Elill Ilx — eill2 where x E Er. (a) Compute V f (x). (b) Compute V2 f (x). (c) Show 1 (x) is a convex function. (d) Find the global optimal solution of mint 1(x).