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Ch. 5 - Systems and Matrices
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
All textbooksLial 13th EditionCh. 5 - Systems and MatricesProblem 23
Chapter 6, Problem 23

Find the inverse, if it exists, for each matrix.[1010−10211]\(\left\)[ \(\begin{matrix}\) 1 & 0 & 1 \\0 & -1 & 0 \\2 & 1 & 1 \(\end{matrix}\) \(\right\)]

Verified step by step guidance
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Identify the given 3x3 matrix \( A \) for which you need to find the inverse.
Calculate the determinant of matrix \( A \) using the formula for a 3x3 matrix determinant: \[ \det(A) = a(ei - fh) - b(di - fg) + c(dh - eg) \] where the matrix elements are: \[ \begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix} \]
Check if the determinant \( \det(A) \) is nonzero. If \( \det(A) = 0 \), the inverse does not exist. If it is nonzero, proceed to the next step.
Find the matrix of minors by calculating the determinant of each 2x2 submatrix formed by removing the row and column of each element.
Form the matrix of cofactors by applying a checkerboard pattern of signs (+, -, +, -, +, -, +, -, +) to the matrix of minors, then transpose this cofactor matrix to get the adjugate matrix. Finally, multiply the adjugate matrix by \( \frac{1}{\det(A)} \) to find the inverse matrix \( A^{-1} \).

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Key Concepts

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

Matrix Inverse

The inverse of a matrix A is another matrix, denoted A⁻¹, such that when multiplied together, they produce the identity matrix. Only square matrices with non-zero determinants have inverses. Finding the inverse is essential for solving matrix equations and understanding linear transformations.
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Determinant of a Matrix

The determinant is a scalar value computed from a square matrix that indicates whether the matrix is invertible. If the determinant is zero, the matrix does not have an inverse. Calculating the determinant is a crucial step before attempting to find the inverse.
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Methods for Finding the Inverse

Common methods to find a matrix inverse include using the adjoint formula, row reduction to the identity matrix, or applying elementary row operations. For a 3x3 matrix, the row reduction method or the formula involving cofactors and the determinant are typically used.
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Related Practice
Textbook Question

Find the partial fraction decomposition for each rational expression. See Examples 1–4. (-3)/(x2(x2 + 5))

Textbook Question

Evaluate each determinant.

∣120−12−1014∣\(\left\)| \(\begin{matrix}\) 1 & 2 & 0 \\ -1 & 2 & -1 \\ 0 & 1 & 4 \(\end{matrix}\) \(\right\)|

Textbook Question

Graph each inequality. y > (x - 1)2 + 2

Textbook Question

Solve each nonlinear system of equations. Give all solutions, including those with nonreal complex components. See Examples 1–5.

x2+y2=102x^2+y^2=102

x2−y2=17x^2-y^2=17

Textbook Question

Solve each system by elimination. In systems with fractions, first clear denominators.

5x + 7y = 6

10x - 3y = 46

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Textbook Question

Use the Gauss-Jordan method to solve each system of equations. For systems in two variables with infinitely many solutions, write the solution with y arbitrary. For systems in three variables with infinitely many solutions, write the solution set with z arbitrary.

3x + 2y = -9

2x - 5y = -6

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