... Lecture Notes: Introduction to Finite Element Method Chapter 1. Introduction© 1998 Yijun Liu, University of Cincinnati 7II. Review of Matrix AlgebraLinear System of Algebraic Equationsa ... : (3)A is called a n×n (square) matrix, and x and b are (column)vectors of dimension n. Lecture Notes: Introduction to Finite Element Method Chapter 1. Introduction© 1998 Yijun Liu, University ... 1, 2, , l; j = 1, 2, , n.Note that, in general, AB BA≠, but ( ) ( )AB C A BC=(associative). Lecture Notes: Introduction to Finite Element Method Chapter 1. Introduction© 1998 Yijun Liu, University...