Calculate adj A, det A, and hence A¯', for the matrix A=| 2 1 -2 -1 1

Algebra and Trigonometry (6th Edition)
6th Edition
ISBN:9780134463216
Author:Robert F. Blitzer
Publisher:Robert F. Blitzer
ChapterP: Prerequisites: Fundamental Concepts Of Algebra
Section: Chapter Questions
Problem 1MCCP: In Exercises 1-25, simplify the given expression or perform the indicated operation (and simplify,...
icon
Related questions
Question
**Calculating the Adjugate, Determinant, and Inverse of a Matrix**

For the matrix \( A \) given by:

\[ A = \begin{bmatrix} 1 & 2 & -3 \\ 2 & 1 & -2 \\ 2 & -1 & 1 \end{bmatrix} \]

we need to perform the following calculations:
  
1. **Adjugate of \( A \) (adj\( A \))**
2. **Determinant of \( A \) (\( \det A \))**
3. **Inverse of \( A \) (\( A^{-1} \))**

**Steps to calculate each:**

1. **Determinant (\( \det A \)):**

\[
\det A = \begin{vmatrix} 1 & 2 & -3 \\ 2 & 1 & -2 \\ 2 & -1 & 1 \end{vmatrix}
\]

Expand the determinant using cofactor expansion along the first row:

\[
\det A = 1 \cdot \begin{vmatrix} 1 & -2 \\ -1 & 1 \end{vmatrix} - 2 \cdot \begin{vmatrix} 2 & -2 \\ 2 & 1 \end{vmatrix} + (-3) \cdot \begin{vmatrix} 2 & 1 \\ 2 & -1 \end{vmatrix}
\]

Calculating each 2x2 determinant:

\[
\begin{vmatrix} 1 & -2 \\ -1 & 1 \end{vmatrix} = (1)(1) - (-1)(-2) = 1 - 2 = -1
\]
\[
\begin{vmatrix} 2 & -2 \\ 2 & 1 \end{vmatrix} = (2)(1) - (2)(-2) = 2 - (-4) = 6
\]

\[
\begin{vmatrix} 2 & 1 \\ 2 & -1 \end{vmatrix} = (2)(-1) - (2)(1) = -2 - 2 = -4
\]

Substitute these back into the determinant formula:

\[
\det A = 1 \cdot (-1) - 2 \cdot
Transcribed Image Text:**Calculating the Adjugate, Determinant, and Inverse of a Matrix** For the matrix \( A \) given by: \[ A = \begin{bmatrix} 1 & 2 & -3 \\ 2 & 1 & -2 \\ 2 & -1 & 1 \end{bmatrix} \] we need to perform the following calculations: 1. **Adjugate of \( A \) (adj\( A \))** 2. **Determinant of \( A \) (\( \det A \))** 3. **Inverse of \( A \) (\( A^{-1} \))** **Steps to calculate each:** 1. **Determinant (\( \det A \)):** \[ \det A = \begin{vmatrix} 1 & 2 & -3 \\ 2 & 1 & -2 \\ 2 & -1 & 1 \end{vmatrix} \] Expand the determinant using cofactor expansion along the first row: \[ \det A = 1 \cdot \begin{vmatrix} 1 & -2 \\ -1 & 1 \end{vmatrix} - 2 \cdot \begin{vmatrix} 2 & -2 \\ 2 & 1 \end{vmatrix} + (-3) \cdot \begin{vmatrix} 2 & 1 \\ 2 & -1 \end{vmatrix} \] Calculating each 2x2 determinant: \[ \begin{vmatrix} 1 & -2 \\ -1 & 1 \end{vmatrix} = (1)(1) - (-1)(-2) = 1 - 2 = -1 \] \[ \begin{vmatrix} 2 & -2 \\ 2 & 1 \end{vmatrix} = (2)(1) - (2)(-2) = 2 - (-4) = 6 \] \[ \begin{vmatrix} 2 & 1 \\ 2 & -1 \end{vmatrix} = (2)(-1) - (2)(1) = -2 - 2 = -4 \] Substitute these back into the determinant formula: \[ \det A = 1 \cdot (-1) - 2 \cdot
Expert Solution
steps

Step by step

Solved in 3 steps with 2 images

Blurred answer
Knowledge Booster
Determinant
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, algebra and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Algebra and Trigonometry (6th Edition)
Algebra and Trigonometry (6th Edition)
Algebra
ISBN:
9780134463216
Author:
Robert F. Blitzer
Publisher:
PEARSON
Contemporary Abstract Algebra
Contemporary Abstract Algebra
Algebra
ISBN:
9781305657960
Author:
Joseph Gallian
Publisher:
Cengage Learning
Linear Algebra: A Modern Introduction
Linear Algebra: A Modern Introduction
Algebra
ISBN:
9781285463247
Author:
David Poole
Publisher:
Cengage Learning
Algebra And Trigonometry (11th Edition)
Algebra And Trigonometry (11th Edition)
Algebra
ISBN:
9780135163078
Author:
Michael Sullivan
Publisher:
PEARSON
Introduction to Linear Algebra, Fifth Edition
Introduction to Linear Algebra, Fifth Edition
Algebra
ISBN:
9780980232776
Author:
Gilbert Strang
Publisher:
Wellesley-Cambridge Press
College Algebra (Collegiate Math)
College Algebra (Collegiate Math)
Algebra
ISBN:
9780077836344
Author:
Julie Miller, Donna Gerken
Publisher:
McGraw-Hill Education