Method, Examples, Meaning | Solve Augmented Matrix - Cuemath

Augmented Matrix

An augmented matrix is a matrix formed by combining the columns of two matrices to form a new matrix. The augmented matrix is an important tool in matrices used to solve simple linear equations. The number of rows in the augmented matrix is equal to the number of variables in the linear equation.

In this article, let us discuss the concept of an augmented matrix and its properties. We will learn how to solve augmented matrix and how it helps to solve a system of linear equations. Let us learn more about how to solve the augmented matrix, the properties of the augmented matrix, with the help of examples.

1.	What Is An Augmented Matrix?
2.	Augmented Matrix Meaning
3.	How To Solve Augmented Matrix?
4.	Properties of Augmented Matrix
5.	Finding Inverse of Matrix Using Augmented Matrix
6.	FAQs on Augmented Matrix

What Is An Augmented Matrix?

An augmented matrix is a means to solve simple linear equations. The coefficients and constant values of the linear equations are represented as a matrix, referred to as an augmented matrix. In simple terms, the augmented matrix is the combination of two simple matrices along the columns. If there are m columns in the first matrix and n columns in the second matrix, then there would be m + n columns in the augmented matrix.

Let us understand the concept of augmented matrix, with the help of three linear equations, represented as follows.

a1x + b1y + c1z = d1

a2x + b2y + c2z = d2

a3x + b3y + c3z = d3

The three above equations can be represented in matrix form with the coefficients as one matrix, the constant terms as another matrix, and the variables as a separate matrix.

Matrix of Coefficients - A = \(\begin{bmatrix} a_1&b_1&c_1\\a_2&b_2&c_2\\a_3&b_3&c_3\end{bmatrix}\)

Matrix of Constant terms - B = \(\begin{bmatrix}d_1\\d_2\\d_3\end{bmatrix}\)

Matrix of Variables - C = \(\begin{bmatrix}x\\y\\z\end{bmatrix}\)

The augmented matrix 'M' can be represented as a matrix after combining the matrices with the coefficient terms and the constant terms.

M = [A | B]

M = \(\begin{bmatrix} a_1&b_1&c_1|&d_1\\a_2&b_2&c_2|&d_2\\a_3&b_3&c_3|&d_3\end{bmatrix}\)

Here M is the augmented matrix and the number of rows in the augmented matrix is equal to the number of linear equations. The coefficients of the x terms are in the first column, the coefficients of the y terms are in the second column, the coefficients of the z term are in the third column, and the constant term is in the last column. The elementary row operations can be easily performed on an augmented matrix to find the solutions to the linear equations.

Augmented Matrix Meaning

An augmented matrix is a matrix that is formed by joining matrices with the same number of rows along the columns. It is used to solve a system of linear equations and to find the inverse of a matrix.

How to Solve Augmented Matrix?

The augmented matrix is solved by performing operations across its rows, and it helps to find the solution to the linear equations represented in the augmented matrix. The augmented matrix contains the coefficient values and the constant terms. Applying the Gauss Jordan Method of row transformation, the operations on rows help in transforming a part of the augmented matrix into an identity matrix. The elements remaining in the last column after the row transformations are the values of the variable of the linear equations.

Let us understand this with the notations from the equations of the line. The three equations of the lines are a1x + b1y + c1z = d1, a2x + b2y + c2z = d2, a3x + b3y +c3z = d3. Let us represent these three equations in the form of an augmented matrix.

A = \(\begin{bmatrix} a_1&b_1&c_1|&d_1\\a_2&b_2&c_2|&d_2\\a_3&b_3&c_3|&d_3\end{bmatrix}\)

Here we can perform numerous row operations to obtain the following matrix. We apply elementary row operations to make the left side of the bar an identity matrix and the right side gives the solution to the system of equations.

A = \(\begin{bmatrix} 1&0&0|&k\\0&1&0|&l\\0&0&1|&m\end{bmatrix}\)

Here the elements in the last row represent the values of the variables, and we have x = k, y = l, z = m, respectively.

Properties Of Augmented Matrix

The following properties help in a better understanding of an augmented matrix.

• The augmented matrix is a rectangular matrix.
• The number of columns is equal to the variables in the linear equations and the constant term.
• The number of rows is equal to the number of linear equations.
• The rows of the augmented matrix can be interchanged.
• The elements of a particular row can be multiplied or divided with a constant.
• The particular row can be added and subtracted to other rows of the matrix.
• The multiple of a row can be added to another row of the matrix.

Finding Inverse of Matrix Using Augmented Matrix

Consider a 3 × 3 matrix A = \(\begin{bmatrix} a_1&b_1&c_1\\a_2&b_2&c_2\\a_3&b_3&c_3\end{bmatrix}\) and to find the inverse of the matrix A, we obtain the augmented matrix (A | I), where I is a 3 × 3 identity matrix. We apply elementary row operations on (A | I) to make the left side of the augmented matrix an identity matrix and obtain the matrix (I | A-1).

Important Notes on Augmented Matrix

• An augmented matrix is a matrix that is formed by joining matrices with the same number of rows along the columns.
• It is used to solve a system of linear equations and to find the inverse of a matrix.
• We can apply elementary row operations on the augmented matrix.

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