Use the determinant theorems to evaluate each determinant. ∣68−12−10240−8∣\left| \begin{matrix} 6 & 8 & -12 \\ -1 & 0 & 2 \\ 4 & 0 & -8 \end{matrix} \right|

Ch. 5 - Systems and Matrices

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Lial 13th Edition

Ch. 5 - Systems and Matrices

문제 47

6장, 문제 47

Use the determinant theorems to evaluate each determinant.
$∣ \begin{matrix} 6 & 8 & - 12 \\ - 1 & 0 & 2 \\ 4 & 0 & - 8 \end{matrix} ∣$

검증된 단계별 안내

Identify the size and structure of the given determinant matrix (e.g., 2x2, 3x3, etc.) to determine which determinant theorems and properties apply.

Recall key determinant theorems such as: the determinant of a triangular matrix is the product of its diagonal entries, swapping two rows changes the sign of the determinant, multiplying a row by a scalar multiplies the determinant by that scalar, and adding a multiple of one row to another row does not change the determinant.

Apply row operations strategically to simplify the determinant calculation, using the theorems to keep track of how these operations affect the determinant value.

Calculate the determinant of the simplified matrix, often by expanding along a row or column or by using the product of diagonal entries if the matrix is triangular.

Combine all the effects of the row operations and the determinant of the simplified matrix to find the determinant of the original matrix.

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Determinant of a Matrix

The determinant is a scalar value computed from a square matrix that provides important properties such as invertibility. It can be calculated using various methods, including expansion by minors or row operations, and is essential for solving systems of linear equations and understanding matrix behavior.

Determinant Theorems

Determinant theorems are rules that simplify the calculation of determinants, such as the effect of row swaps, scalar multiplication of rows, and adding multiples of one row to another. These theorems help reduce complex determinants into easier forms without changing their value or by adjusting it predictably.

Row Operations and Their Impact on Determinants

Certain row operations affect the determinant in specific ways: swapping two rows multiplies the determinant by -1, multiplying a row by a scalar multiplies the determinant by that scalar, and adding a multiple of one row to another does not change the determinant. Understanding these effects is crucial for efficient determinant evaluation.

Use the determinant theorems to evaluate each determinant. ∣68−12−10240−8∣\(\left\)| \(\begin{matrix}\) 6 & 8 & -12 \\ -1 & 0 & 2 \\ 4 & 0 & -8 \(\end{matrix}\) \(\right\)|