MATH M118 Lecture Notes - Lecture 9: Single-Photon Emission Computed Tomography
2 Nov 2016
School
Department
Course
Professor
Document Summary
We will learn the basic operations of matrix algebra, focusing on addition, subtraction, and multiplication. Before we start, it is important to understand the dimensions of a matrix. Every matrix has a certain number of rows (m) and a certain number of columns (n). So, we define the dimensions of a matrix to be # of rows by # of columns (m x n). Let"s fi(cid:374)d the di(cid:373)e(cid:374)sio(cid:374)s of a few (cid:373)at(cid:396)i(cid:272)es. What are the dimensions of the following matrices? (cid:2779: (cid:2157)=[(cid:2784) (cid:2781)] 3 x 2 (cid:2158)=[(cid:2777) (cid:2779) (cid:2778) (cid:2783) (cid:2784)] (cid:2779) Matrix addition/subtraction: matrices can be added/subtracted if and only if the dimensions of the two matrices are the same. So, if a is a 2x3 matrix, we can only add/subtract it to matrix b, if b is also a 2x3 matrix. If the dimensions are different, then the sum/difference is not possible: adding/subtracting matrices is a very straightforward operation.
