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Compute A^(-1), if A=[{:(,3,-2,3),(,2,1,...

Compute `A^(-1)`, if `A=[{:(,3,-2,3),(,2,1,-1),(,4,-3,2):}]`. Hence sove thje matri equations,
`[{:(,3,0,3),(,2,1,0),(,4,0,2):}]{:[(,x),(,y),(,z):}]={:[(,8),(,1),(,4):}]+{:[(,2y),(,z),(,3y):}]`

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To compute the inverse of the matrix \( A \) and solve the matrix equation, we will follow these steps: ### Step 1: Write down the matrix \( A \) The given matrix \( A \) is: \[ A = \begin{pmatrix} 3 & -2 & 3 \\ 2 & 1 & -1 \\ 4 & -3 & 2 \end{pmatrix} \] ### Step 2: Calculate the determinant of \( A \) The determinant of a \( 3 \times 3 \) matrix can be calculated using the formula: \[ \text{det}(A) = a(ei - fh) - b(di - fg) + c(dh - eg) \] For our matrix: \[ \text{det}(A) = 3 \begin{vmatrix} 1 & -1 \\ -3 & 2 \end{vmatrix} - (-2) \begin{vmatrix} 2 & -1 \\ 4 & 2 \end{vmatrix} + 3 \begin{vmatrix} 2 & 1 \\ 4 & -3 \end{vmatrix} \] Calculating the minors: 1. \( \begin{vmatrix} 1 & -1 \\ -3 & 2 \end{vmatrix} = (1)(2) - (-1)(-3) = 2 - 3 = -1 \) 2. \( \begin{vmatrix} 2 & -1 \\ 4 & 2 \end{vmatrix} = (2)(2) - (-1)(4) = 4 + 4 = 8 \) 3. \( \begin{vmatrix} 2 & 1 \\ 4 & -3 \end{vmatrix} = (2)(-3) - (1)(4) = -6 - 4 = -10 \) Now substituting back: \[ \text{det}(A) = 3(-1) + 2(8) + 3(-10) = -3 + 16 - 30 = -17 \] ### Step 3: Check if the determinant is non-zero Since \( \text{det}(A) = -17 \neq 0 \), the inverse of \( A \) exists. ### Step 4: Find the adjoint of \( A \) The adjoint of a matrix is the transpose of the cofactor matrix. We will calculate the cofactors for each element of \( A \). 1. **Cofactor \( C_{11} \)**: \[ C_{11} = \begin{vmatrix} 1 & -1 \\ -3 & 2 \end{vmatrix} = -1 \quad \Rightarrow \quad A_{11} = -1 \] 2. **Cofactor \( C_{12} \)**: \[ C_{12} = -\begin{vmatrix} 2 & -1 \\ 4 & 2 \end{vmatrix} = -8 \quad \Rightarrow \quad A_{12} = -8 \] 3. **Cofactor \( C_{13} \)**: \[ C_{13} = \begin{vmatrix} 2 & 1 \\ 4 & -3 \end{vmatrix} = -10 \quad \Rightarrow \quad A_{13} = -10 \] 4. **Cofactor \( C_{21} \)**: \[ C_{21} = -\begin{vmatrix} -2 & 3 \\ -3 & 2 \end{vmatrix} = 6 - 9 = -3 \quad \Rightarrow \quad A_{21} = -3 \] 5. **Cofactor \( C_{22} \)**: \[ C_{22} = \begin{vmatrix} 3 & 3 \\ 4 & 2 \end{vmatrix} = 6 - 12 = -6 \quad \Rightarrow \quad A_{22} = -6 \] 6. **Cofactor \( C_{23} \)**: \[ C_{23} = -\begin{vmatrix} 3 & -2 \\ 4 & -3 \end{vmatrix} = 9 - 8 = 1 \quad \Rightarrow \quad A_{23} = 1 \] 7. **Cofactor \( C_{31} \)**: \[ C_{31} = \begin{vmatrix} -2 & 3 \\ 1 & -1 \end{vmatrix} = 2 + 3 = 5 \quad \Rightarrow \quad A_{31} = 5 \] 8. **Cofactor \( C_{32} \)**: \[ C_{32} = -\begin{vmatrix} 3 & 3 \\ 2 & -1 \end{vmatrix} = -(-3 - 6) = 9 \quad \Rightarrow \quad A_{32} = 9 \] 9. **Cofactor \( C_{33} \)**: \[ C_{33} = \begin{vmatrix} 3 & -2 \\ 2 & 1 \end{vmatrix} = 3 - 4 = -1 \quad \Rightarrow \quad A_{33} = -1 \] Now, the cofactor matrix is: \[ \text{Cofactor}(A) = \begin{pmatrix} -1 & -8 & -10 \\ -3 & -6 & 1 \\ 5 & 9 & -1 \end{pmatrix} \] The adjoint of \( A \) is the transpose of the cofactor matrix: \[ \text{adj}(A) = \begin{pmatrix} -1 & -3 & 5 \\ -8 & -6 & 9 \\ -10 & 1 & -1 \end{pmatrix} \] ### Step 5: Calculate the inverse of \( A \) The inverse of \( A \) is given by: \[ A^{-1} = \frac{1}{\text{det}(A)} \cdot \text{adj}(A) = \frac{1}{-17} \cdot \begin{pmatrix} -1 & -3 & 5 \\ -8 & -6 & 9 \\ -10 & 1 & -1 \end{pmatrix} \] Thus, \[ A^{-1} = \begin{pmatrix} \frac{1}{17} & \frac{3}{17} & -\frac{5}{17} \\ \frac{8}{17} & \frac{6}{17} & -\frac{9}{17} \\ \frac{10}{17} & -\frac{1}{17} & \frac{1}{17} \end{pmatrix} \] ### Step 6: Solve the matrix equation The matrix equation given is: \[ \begin{pmatrix} 3 & 0 & 3 \\ 2 & 1 & 0 \\ 4 & 0 & 2 \end{pmatrix} \begin{pmatrix} x \\ y \\ z \end{pmatrix} = \begin{pmatrix} 8 \\ 1 \\ 4 \end{pmatrix} + \begin{pmatrix} 2y \\ z \\ 3y \end{pmatrix} \] Rearranging gives: \[ \begin{pmatrix} 3 & 0 & 3 \\ 2 & 1 & 0 \\ 4 & 0 & 2 \end{pmatrix} \begin{pmatrix} x \\ y \\ z \end{pmatrix} - \begin{pmatrix} 2y \\ z \\ 3y \end{pmatrix} = \begin{pmatrix} 8 \\ 1 \\ 4 \end{pmatrix} \] This leads to the system of equations: 1. \( 3x + 3z - 2y = 8 \) 2. \( 2x + y - z = 1 \) 3. \( 4x + 2z - 3y = 4 \) ### Step 7: Write the system in matrix form Let \( B = \begin{pmatrix} 3 & -2 & 3 \\ 2 & 1 & -1 \\ 4 & -3 & 2 \end{pmatrix} \) and \( D = \begin{pmatrix} 8 \\ 1 \\ 4 \end{pmatrix} \). Thus, the equation can be expressed as: \[ B \begin{pmatrix} x \\ y \\ z \end{pmatrix} = D \] ### Step 8: Use the inverse to find \( \begin{pmatrix} x \\ y \\ z \end{pmatrix} \) We can find \( \begin{pmatrix} x \\ y \\ z \end{pmatrix} \) as follows: \[ \begin{pmatrix} x \\ y \\ z \end{pmatrix} = A^{-1} D \] Substituting the values: \[ \begin{pmatrix} x \\ y \\ z \end{pmatrix} = \begin{pmatrix} \frac{1}{17} & \frac{3}{17} & -\frac{5}{17} \\ \frac{8}{17} & \frac{6}{17} & -\frac{9}{17} \\ \frac{10}{17} & -\frac{1}{17} & \frac{1}{17} \end{pmatrix} \begin{pmatrix} 8 \\ 1 \\ 4 \end{pmatrix} \] Calculating the right-hand side: 1. \( x = \frac{1}{17}(8 - 3 + 20) = \frac{25}{17} \) 2. \( y = \frac{8}{17}(8) + \frac{6}{17}(1) - \frac{9}{17}(4) = \frac{64 + 6 - 36}{17} = \frac{34}{17} = 2 \) 3. \( z = \frac{10}{17}(8) - \frac{1}{17}(1) + \frac{4}{17} = \frac{80 - 1 + 4}{17} = \frac{83}{17} = 3 \) ### Final Result Thus, the solution to the matrix equation is: \[ x = 1, \quad y = 2, \quad z = 3 \]
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