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The inverse of matrix [[-1, 5], [-3, 2]]...

The inverse of matrix `[[-1, 5], [-3, 2]]` is

A

`(1)/(13)[[2, -5], [3, -1]]`

B

`(1)/(13)[[-1, 5], [-3, 2]]`

C

`(1)/(13)[[-1, -3], [5, 2]]`

D

`(1)/(13)[[1, 5], [3, -2]]`

Text Solution

AI Generated Solution

The correct Answer is:
To find the inverse of the matrix \(\begin{bmatrix} -1 & 5 \\ -3 & 2 \end{bmatrix}\), we will follow these steps: ### Step 1: Define the Matrix Let \( A = \begin{bmatrix} -1 & 5 \\ -3 & 2 \end{bmatrix} \). ### Step 2: Calculate the Determinant of Matrix A The determinant of a \(2 \times 2\) matrix \(\begin{bmatrix} a & b \\ c & d \end{bmatrix}\) is calculated using the formula: \[ \text{det}(A) = ad - bc \] For our matrix \( A \): - \( a = -1 \) - \( b = 5 \) - \( c = -3 \) - \( d = 2 \) Calculating the determinant: \[ \text{det}(A) = (-1)(2) - (5)(-3) = -2 + 15 = 13 \] ### Step 3: Check if the Determinant is Non-Zero Since \(\text{det}(A) = 13\) (which is not equal to zero), the inverse of matrix \( A \) exists. ### Step 4: Find the Adjoint of Matrix A The adjoint of a \(2 \times 2\) matrix \(\begin{bmatrix} a & b \\ c & d \end{bmatrix}\) is given by: \[ \text{adj}(A) = \begin{bmatrix} d & -b \\ -c & a \end{bmatrix} \] For our matrix \( A \): - \( d = 2 \) - \( -b = -5 \) - \( -c = 3 \) - \( a = -1 \) Thus, the adjoint of \( A \) is: \[ \text{adj}(A) = \begin{bmatrix} 2 & -5 \\ 3 & -1 \end{bmatrix} \] ### Step 5: Calculate the Inverse of Matrix A The inverse of matrix \( A \) is given by the formula: \[ A^{-1} = \frac{1}{\text{det}(A)} \cdot \text{adj}(A) \] Substituting the values we found: \[ A^{-1} = \frac{1}{13} \cdot \begin{bmatrix} 2 & -5 \\ 3 & -1 \end{bmatrix} \] This results in: \[ A^{-1} = \begin{bmatrix} \frac{2}{13} & -\frac{5}{13} \\ \frac{3}{13} & -\frac{1}{13} \end{bmatrix} \] ### Final Answer The inverse of the matrix \(\begin{bmatrix} -1 & 5 \\ -3 & 2 \end{bmatrix}\) is: \[ A^{-1} = \begin{bmatrix} \frac{2}{13} & -\frac{5}{13} \\ \frac{3}{13} & -\frac{1}{13} \end{bmatrix} \] ---
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