Matrix Inverse 4Da62E
1. **Problem:** Find the inverse of the matrix $A$ using the adjoint method.
2. **Formula:** The inverse of a matrix $A$ is given by
$$A^{-1} = \frac{1}{|A|} \times \text{adj}(A)$$
where $|A|$ is the determinant of $A$ and $\text{adj}(A)$ is the adjoint (transpose of cofactor matrix).
3. **Step 1: Calculate the Determinant $|A|$**
Calculate determinant to ensure it is non-zero:
$$|A| = 1(4 - 2) - 0 + 1(-1 - 2) = 2 - 3 = -1$$
Since $|A| = -1 \neq 0$, inverse exists.
4. **Step 2: Matrix of Cofactors $C$**
Calculate each cofactor:
$$C = \begin{bmatrix} 2 & 4 & -3 \\ 1 & 1 & -1 \\ -2 & -3 & 2 \end{bmatrix}$$
5. **Step 3: Adjoint Matrix $\text{adj}(A)$**
Transpose the cofactor matrix:
$$\text{adj}(A) = C^T = \begin{bmatrix} 2 & 1 & -2 \\ 4 & 1 & -3 \\ -3 & -1 & 2 \end{bmatrix}$$
6. **Step 4: Calculate the Inverse**
Multiply adjoint by $1/|A| = -1$:
$$A^{-1} = -1 \times \begin{bmatrix} 2 & 1 & -2 \\ 4 & 1 & -3 \\ -3 & -1 & 2 \end{bmatrix} = \begin{bmatrix} -2 & -1 & 2 \\ -4 & -1 & 3 \\ 3 & 1 & -2 \end{bmatrix}$$
**Final Answer:**
$$A^{-1} = \begin{bmatrix} -2 & -1 & 2 \\ -4 & -1 & 3 \\ 3 & 1 & -2 \end{bmatrix}$$