Determinant of a 4x4 matrix is a number that represents the size and orientation of the matrix. It is calculated by multiplying certain elements of the matrix together in a specific order and then adding or subtracting the results based on the position of the elements in the matrix. How to Find The Determinant of a 4x4 Matrix (Shortcut Method) 183,009 views 1.8K In this video I will show you a short and effective way of finding the determinant without using cofactors. Instead, a better approach is to use the Gauss Elimination method to convert the original matrix into an upper triangular matrix. The determinant of a lower or an upper triangular matrix is simply the product of the diagonal elements. Here we show an example. To calculate the determinant of a specific matrix in R, you can use the "det ()" function. The determinant of a matrix is the scalar value or number calculated using a square matrix. The square matrix could be 2×2, 3×3, 4×4, or any type, such as n × n, where the number of columns and rows are equal. So here we go (along the first row): $$ \det A = \begin{vmatrix} 5 & -7 & 2 & 2 \\ 0 & 3 & 0 & -4 \\ -5 & -8 & 0 & 3 \\ 0 & 5 & 0 & -6 \\ \end{vmatrix} = 5 \begin{vmatrix} 3 & 0 & -4 \\ -8 & 0 & 3 \\ 5 & 0 & -6 \\ \end{vmatrix} -(-7) \begin{vmatrix} 0 & 0 & -4 \\ -5 & 0 & 3 \\ 0 & 0 & -6 \\ \end{vmatrix} + 2 \begin{vmatrix} 0 & 3 & -4 \\ -5 Every time I reduced this to row echelon form, I got $\dfrac{1}{48}$ as the determinant when the actual determinant is $48$. Here are the row operations. The rows that I have highlighted are the ones that change the determinant since we are changing a row by a factor. All the other operations don't change the determinant and we never switch Determinant of a Matrix The determinant is a special number that can be calculated from a matrix. The matrix has to be square (same number of rows and columns) like this one: 3 8 4 6 A Matrix (This one has 2 Rows and 2 Columns) Let us calculate the determinant of that matrix: 3×6 − 8×4 = 18 − 32 = −14 Easy, hey? Here is another example: Example: Testing for a zero determinant. Look at what always happens when c=a. Disaster for invertibility. The determinant for that kind of a matrix must always be zero. When you get an equation like this for a determinant, set it equal to zero and see what happens! Those are by definition a description of all your singular matrices. The determinant of a matrix is the scalar value or number calculated using a square matrix. The square matrix could be 2×2, 3×3, 4×4, or any type, such as n × n, where the number of column and rows are equal. If S is the set of square matrices, R is the set of numbers (real or complex) and f : S → R is defined by f (A) = k, where A ∈ S The first step in computing the determinant of a 4×4 matrix is to make zero all the elements of a column except one using elementary row operations. We can perform elementary row operations thanks to the properties of determinants. In this case, the first column already has a zero. jyh8TEZ.