Chapter 6: Problem 3
Compute the inverse matrix. $$ \left[\begin{array}{ll} 0 & 1 \\ 1 & 0 \end{array}\right] $$
Short Answer
Expert verified
The inverse matrix is \(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\).
Step by step solution
01
- Write Down the Given Matrix
The matrix provided is: \[\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\]
02
- Identify the Determinant of the Matrix
Calculate the determinant of the matrix. For a 2x2 matrix \(\begin{pmatrix} a & b \ c & d \end{pmatrix} \), the determinant is given by \(AD - BC \). Substituting the values from the matrix, we get: Det = (0 \cdot 0) - (1 \cdot 1) = -1
03
- Create the Adjugate Matrix
The adjugate matrix for a 2x2 matrix \(\begin{pmatrix} a & b \ c & d \end{pmatrix} \) is obtained by swapping the elements on the main diagonal and changing the signs of the off-diagonal elements. For the given matrix, the adjugate matrix is:\[\begin{pmatrix} 0 & -1 \ -1 & 0 \end{pmatrix}\]
04
- Calculate the Inverse Matrix
The inverse of a matrix is given by dividing the adjugate matrix by the determinant. Therefore, the inverse matrix is:\(\frac{1} {-1} \cdot\begin{pmatrix} 0 & -1 \ -1 & 0 \end{pmatrix}\) =\[\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Determinant
A determinant is a special number that can be calculated from a square matrix. It tells us various properties of the matrix, including whether it has an inverse. For a 2x2 matrix \(\begin{pmatrix} a & b \ c & d \end{pmatrix}\), the determinant is calculated using the formula: Det = ad - bc.
In our given matrix \(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\), we substitute the values into the formula:
Det = (0 \cdot 0) - (1 \cdot 1) = -1
The determinant is -1. This non-zero value confirms that our matrix has an inverse.
In our given matrix \(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\), we substitute the values into the formula:
Det = (0 \cdot 0) - (1 \cdot 1) = -1
The determinant is -1. This non-zero value confirms that our matrix has an inverse.
Adjugate Matrix
The adjugate of a matrix is the transpose of its cofactor matrix. However, for a 2x2 matrix, finding the adjugate is simpler. You just swap the elements of the main diagonal and change the signs of the off-diagonal elements.
For matrix \(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\), the adjugate is calculated as follows:
Original matrix: \(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\)
Adjugate matrix: \(\begin{pmatrix} 0 & -1 \ -1 & 0 \end{pmatrix}\)
This adjugate matrix will be used in the final step to find the inverse.
For matrix \(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\), the adjugate is calculated as follows:
Original matrix: \(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\)
Adjugate matrix: \(\begin{pmatrix} 0 & -1 \ -1 & 0 \end{pmatrix}\)
This adjugate matrix will be used in the final step to find the inverse.
Matrix Inversion
Matrix inversion is the process of finding a matrix that, when multiplied by the original matrix, yields the identity matrix. For a 2x2 matrix, the inverse is computed by dividing the adjugate matrix by the determinant.
The formula for the inverse of a 2x2 matrix \(\begin{pmatrix} a & b \ c & d \end{pmatrix}\) is:
Inverse = \(\frac{1}{det(A)} \cdot adj(A)\)
In our case, the determinant is -1 and the adjugate matrix is \(\begin{pmatrix} 0 & -1 \ -1 & 0 \end{pmatrix}\). Therefore,
Inverse matrix = \(\frac{1}{-1} \cdot \begin{pmatrix} 0 & -1 \ -1 & 0 \end{pmatrix}\)
Perform the multiplication:
Inverse matrix = \(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\)
The formula for the inverse of a 2x2 matrix \(\begin{pmatrix} a & b \ c & d \end{pmatrix}\) is:
Inverse = \(\frac{1}{det(A)} \cdot adj(A)\)
In our case, the determinant is -1 and the adjugate matrix is \(\begin{pmatrix} 0 & -1 \ -1 & 0 \end{pmatrix}\). Therefore,
Inverse matrix = \(\frac{1}{-1} \cdot \begin{pmatrix} 0 & -1 \ -1 & 0 \end{pmatrix}\)
Perform the multiplication:
Inverse matrix = \(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\)
2x2 Matrix
A 2x2 matrix is a matrix with two rows and two columns. It is one of the simplest forms of a square matrix and is often used to introduce basic concepts of linear algebra.
In our exercise, we are given a 2x2 matrix:
\(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\)
This matrix has the following properties:
Understanding 2x2 matrices helps build a foundation for grasping more complex matrix concepts and operations.
In our exercise, we are given a 2x2 matrix:
\(\begin{pmatrix} 0 & 1 \ 1 & 0 \end{pmatrix}\)
This matrix has the following properties:
- Two rows and two columns
- The elements are arranged in a grid format.
- It can represent transformations in a 2-dimensional space.
Understanding 2x2 matrices helps build a foundation for grasping more complex matrix concepts and operations.