Try the fastest way to create flashcards
Question

List the minor matrix MijM_{ij}, and calculate the cofactor Aij=(1)i+jdet(Mij)A_{i j}=(-1)^{i+j} \operatorname{det}\left(M_{i j}\right) for the matrix A given by

A=[2131413162412202]A=\left[\begin{array}{rrrr} 2 & -1 & 3 & 1 \\ 4 & 1 & 3 & -1 \\ 6 & 2 & 4 & 1 \\ 2 & 2 & 0 & -2 \end{array}\right]

M11M_{11}

Solution

Verified
Step 1
1 of 2

We have

A=[2131413162412202]\begin{align*} A&=\begin{bmatrix} 2&-1&3&1\\ 4&1&3&-1\\ 6&2&4&1\\ 2&2&0&-2 \end{bmatrix} \end{align*}

Find M11M_{11}, according to Definition 3\text{\color{#c34632}Definition 3}, the minor matrix M11M_{11} is the determinant of the matrix AA formed by deleting the first row and the first column from the matrix AA, then

M11=[131241202]\begin{align*} M_{11}&=\begin{bmatrix} 1&3&-1\\ 2&4&1\\ 2&0&-2 \end{bmatrix} \end{align*}

then find

A11=(1)1+1det(M11)=det131241202=1det41023det21221det2420=1(80)3(42)1(08)=8+18+8=18\begin{align*} A_{11}&=(-1)^{1+1}\det (M_{11})\\ &=\det \begin{vmatrix} 1&3&-1\\ 2&4&1\\ 2&0&-2 \end{vmatrix}\\ &=1\cdot \det \begin{vmatrix} 4&1\\ 0&-2 \end{vmatrix}-3\cdot \det \begin{vmatrix} 2&1\\ 2&-2 \end{vmatrix}-1\cdot \det \begin{vmatrix} 2&4\\ 2&0 \end{vmatrix}\\ &=1(-8-0)-3(-4-2)-1(0-8)\\ &=-8+18+8\\ &=18 \end{align*}

Hence, M11=18M_{11}=18.

Create a free account to view solutions

Create a free account to view solutions

Recommended textbook solutions

Introduction to Linear Algebra 5th Edition by Jimmy T Arnold, Lee W. Johnson, R Dean Riess

Introduction to Linear Algebra

5th EditionISBN: 9780201658590Jimmy T Arnold, Lee W. Johnson, R Dean Riess
1,931 solutions
Linear Algebra and Its Applications 5th Edition by David C. Lay, Judi J. McDonald, Steven R. Lay

Linear Algebra and Its Applications

5th EditionISBN: 9780321982384 (3 more)David C. Lay, Judi J. McDonald, Steven R. Lay
2,070 solutions
Elementary Linear Algebra 11th Edition by Howard Anton

Elementary Linear Algebra

11th EditionISBN: 9781118473504Howard Anton
2,932 solutions
Elementary Linear Algebra 12th Edition by Anton Kaul, Howard Anton

Elementary Linear Algebra

12th EditionISBN: 9781119406778Anton Kaul, Howard Anton
3,078 solutions

More related questions

1/4

1/7