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Find the inverse of the following matrix:

[tex]
B = \left(\begin{array}{ccc}
3 & 4 & -1 \\
1 & 0 & 3 \\
2 & 5 & -4
\end{array}\right)
[/tex]


Sagot :

To find the inverse of matrix [tex]\( B \)[/tex], we need to determine [tex]\( B^{-1} \)[/tex] such that [tex]\( B \cdot B^{-1} = I \)[/tex], where [tex]\( I \)[/tex] is the identity matrix. To solve for [tex]\( B^{-1} \)[/tex], we use methods such as Gaussian elimination, the adjoint method, or matrix algebra properties.

Given matrix [tex]\( B \)[/tex]:
[tex]\[ B = \begin{pmatrix} 3 & 4 & -1 \\ 1 & 0 & 3 \\ 2 & 5 & -4 \end{pmatrix} \][/tex]

The inverse [tex]\( B^{-1} \)[/tex] is:
[tex]\[ B^{-1} = \begin{pmatrix} 1.5 & -1.1 & -1.2 \\ -1 & 1 & 1 \\ -0.5 & 0.7 & 0.4 \end{pmatrix} \][/tex]

This matrix, when multiplied by [tex]\( B \)[/tex], gives the identity matrix. This solution matrix can be verified through matrix multiplication, ensuring that:
[tex]\[ B \cdot B^{-1} = I, \][/tex]
where [tex]\( I \)[/tex] is the [tex]\( 3 \times 3 \)[/tex] identity matrix:
[tex]\[ I = \begin{pmatrix} 1 & 0 & 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1 \end{pmatrix} \][/tex]

Thus, the inverse of matrix [tex]\( B \)[/tex] is:
[tex]\[ B^{-1} = \begin{pmatrix} 1.5 & -1.1 & -1.2 \\ -1 & 1 & 1 \\ -0.5 & 0.7 & 0.4 \end{pmatrix} \][/tex]

This result is derived by appropriately solving the matrix equations and verifying the correctness of [tex]\( B^{-1} \)[/tex].