.PROBLEM 1: True or False. You don't have to justify. a) Let A and B be nxn matrices, then AB=BA. b) The set of vector ((0,0)) in R2 is linearly independent. c) The basis of a (finite dimensional) vector space is not unique. d) A trial solution for y" - y'=e' is yp= Ate¹ e) A general solution to an nth order differential equation doesn't have to contain n constants.