This section provides materials for a session on matrix methods for solving constant coefficient linear systems of differential equations. Materials include course notes, lecture video clips, JavaScript Mathlets, practice problems with solutions, problem solving videos, and problem sets with solutions. Suppose A is an matrix. 1. We call the number of free variables of A x = b the nullity of A and we denote it by. 2. We call the number of pivots of A the rank of A and we denoted it by . Procedure for computing the rank of a matrix A: 1. Use elementary row operations to transform A to a matrix R in reduced row echelon form. 2. is the number of ...