Chapter 5: Problem 5
Evaluate the given determinants. $$\left|\begin{array}{ll} 8 & 3 \\ 4 & 1 \end{array}\right|$$
Short Answer
Expert verified
The determinant of the matrix is -4.
Step by step solution
01
Identify the Determinant Formula
For a 2x2 matrix of the form: \(\begin{pmatrix} a & b \ c & d \end{pmatrix}\), the determinant \(D\) is calculated using the formula: \(D = ad - bc\).
02
Substitute Values into the Formula
Given the matrix \(\begin{pmatrix} 8 & 3 \ 4 & 1 \end{pmatrix}\), identify \(a = 8\), \(b = 3\), \(c = 4\), and \(d = 1\). Substitute these into the formula: \(D = (8)(1) - (3)(4)\).
03
Calculate Each Component
Calculate \(8 \times 1\) which equals \(8\), and \(3 \times 4\) which equals \(12\).
04
Compute the Determinant
Subtract the values obtained: \(8 - 12 = -4\). Therefore, the determinant of the matrix is \(-4\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding the 2x2 Matrix
A 2x2 matrix is a simple form of square matrix with two rows and two columns. In this structured grid, each element is positioned by its row and column number. For instance, in a matrix like this:
\[\begin{pmatrix} a & b \ c & d \end{pmatrix},\]
- the elements \(a\) and \(b\) are located in the first row,- while \(c\) and \(d\) are in the second row.
It’s crucial to note these positions as they play a significant role in computations like finding the determinant, as each position corresponds to a specific part of the determinant formula.
Mastering the configuration of a 2x2 matrix is fundamental to performing accurate calculations and understanding more complex matrix operations.
\[\begin{pmatrix} a & b \ c & d \end{pmatrix},\]
- the elements \(a\) and \(b\) are located in the first row,- while \(c\) and \(d\) are in the second row.
It’s crucial to note these positions as they play a significant role in computations like finding the determinant, as each position corresponds to a specific part of the determinant formula.
Mastering the configuration of a 2x2 matrix is fundamental to performing accurate calculations and understanding more complex matrix operations.
Exploring Matrix Multiplication
Matrix multiplication is a fundamental operation in matrix algebra, involving combining rows of the first matrix with columns of a second. However, for our 2x2 scenario, let's keep it simple. When you multiply two 2x2 matrices, you produce another 2x2 matrix:
\[\begin{pmatrix}a & b \c & d\end{pmatrix}\times\begin{pmatrix}e & f \g & h\end{pmatrix}=\begin{pmatrix}ae+bg & af+bh \ce+dg & cf+dh\end{pmatrix}\]
To clear it up:
\[\begin{pmatrix}a & b \c & d\end{pmatrix}\times\begin{pmatrix}e & f \g & h\end{pmatrix}=\begin{pmatrix}ae+bg & af+bh \ce+dg & cf+dh\end{pmatrix}\]
To clear it up:
- The top-left element in the new matrix is computed by multiplying the top row of the first matrix by the left column of the second.
- For the top-right, multiply the top row of the first matrix by the right column of the second.
- The same logic applies to the bottom row of the resulting matrix.
Diving into Matrix Algebra
Matrix algebra encompasses a broad set of rules for performing operations on matrices, similar to regular arithmetic but more structured due to the grid-like nature of matrices. At its core, matrix algebra involves operations such as matrix addition, subtraction, multiplication, and finding the determinant or inverse of a matrix.
For example, understanding the determinant, which signifies whether a matrix has an inverse, begins with our 2x2 matrices. The determinant formula is part of matrix algebra’s fundamental techniques:
For a matrix \(\begin{pmatrix} a & b \ c & d \end{pmatrix}\), the determinant is found using:\[ D = ad - bc \]
Beyond calculations, matrix algebra is essential in many fields like computer graphics, data analysis, and linear equations.
For example, understanding the determinant, which signifies whether a matrix has an inverse, begins with our 2x2 matrices. The determinant formula is part of matrix algebra’s fundamental techniques:
For a matrix \(\begin{pmatrix} a & b \ c & d \end{pmatrix}\), the determinant is found using:\[ D = ad - bc \]
Beyond calculations, matrix algebra is essential in many fields like computer graphics, data analysis, and linear equations.
- In graphics, matrices rotate, scale, and transform images seamlessly.
- In computational applications, they organize vast datasets for algorithms to process efficiently.