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Ch. 6 - Matrices and Determinants
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 7, Problem 3

a. Give the order of each matrix.


b. If A = [aᵢⱼ] , identify a₃₂ and a₂₃, or explain why identification is not possible.
[15πe076π2121115]\(\begin{bmatrix}\)1 & -5 & \(\pi\) & e \\0 & 7 & -6 & -\(\pi\) \\-2 & \(\frac{1}{2}\) & 11 & -\(\frac{1}{5}\]\end{bmatrix}\)

Verified step by step guidance
1
Step 1: Identify the order of the matrix by counting the number of rows and columns. The matrix has 3 rows and 4 columns, so its order is \(3 \times 4\).
Step 2: Understand the notation \(A = [a_{ij}]\), where \(a_{ij}\) represents the element in the \(i^{th}\) row and \(j^{th}\) column of matrix \(A\).
Step 3: To find \(a_{32}\), locate the element in the 3rd row and 2nd column of the matrix. This corresponds to the value \(\frac{1}{2}\).
Step 4: To find \(a_{23}\), locate the element in the 2nd row and 3rd column of the matrix. This corresponds to the value \(-6\).
Step 5: Summarize the findings: The order of the matrix is \(3 \times 4\), \(a_{32} = \frac{1}{2}\), and \(a_{23} = -6\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Matrix Order

The order of a matrix is defined by the number of its rows and columns, expressed as 'rows × columns'. It helps in identifying the size and structure of the matrix, which is essential for performing operations like addition, multiplication, or finding specific elements.
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Matrix Element Notation (a_ij)

In matrix notation, a_ij represents the element located in the i-th row and j-th column of matrix A. Understanding this notation is crucial for identifying or manipulating specific elements within the matrix, such as a_32 (3rd row, 2nd column) or a_23 (2nd row, 3rd column).
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Matrix Representation and Interpretation

A matrix is typically enclosed in brackets and contains elements arranged in rows and columns. Interpreting the matrix correctly, including recognizing special values like π or fractions, is important for accurate identification of elements and understanding the matrix's properties.
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