Lesson 7: Determinants II

This document provides information about determinants of matrices including: 1) It defines the determinant of a 2x2 matrix as a11a22 - a12a21 and provides patterns for calculating the determinant of a 3x3 matrix. 2) It explains that the determinant of an nxn matrix is the sum of all products of n elements with one from each row and column, with a positive or negative sign depending on the number of upward lines. 3) It describes how to calculate the determinant of a 3x3 matrix using cofactors, which are minors multiplied by positive or negative one. The determinant is then expressed as a sum of entries multiplied by their cofactors.