How to use Triangle's Rule in Finding Determinant of a 3x3 Matrix

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Calculation of a 3x3 matrix determinant using Triangle's Rule.




The Triangle’s rule will be formed with this scheme:


                
                  

    

The product of diagonal elements and product of elements in the both vertex of two triangles of the first determinant get the “+” sign and the product of diagonal elements and product of elements in the both vertex of two triangles of the second determinant get the “-” sign. In base of triangle’s rule, we have:



This method is somehow similar to Sarrus Rule.

Example 1. Find the determinant of matrix A.

Solution:




Example 2. Find the determinant of matrix B.

Solution:


| BS in Math | MS in Applied Math (30-units earned) | MS in Pure and Applied Math (Thesis still on progress) | Full-time Private Tutor | Online Math Instructor |

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