Discover the answers you need at Westonci.ca, a dynamic Q&A platform where knowledge is shared freely by a community of experts. Join our platform to get reliable answers to your questions from a knowledgeable community of experts. Get quick and reliable solutions to your questions from a community of experienced experts on our platform.

Find the inverse of the matrix below. If necessary, round to the nearest hundredth.

[tex]\[
\left[\begin{array}{cc}
2 & 0 \\
9 & 1
\end{array}\right]
\][/tex]


Sagot :

To find the inverse of the matrix

[tex]\[ \begin{pmatrix} 2 & 0 \\ 9 & 1 \end{pmatrix}, \][/tex]

we follow these steps:

### Step 1: Determine the determinant
The determinant of the matrix

[tex]\[ \begin{pmatrix} a & b \\ c & d \end{pmatrix} \][/tex]

is calculated as

[tex]\[ \text{det} = ad - bc. \][/tex]

For our specific matrix:

[tex]\[ \begin{pmatrix} a & b \\ c & d \end{pmatrix} = \begin{pmatrix} 2 & 0 \\ 9 & 1 \end{pmatrix}, \][/tex]

the determinant is:

[tex]\[ \text{det} = (2)(1) - (0)(9) = 2. \][/tex]

### Step 2: Check if the determinant is non-zero
Since the determinant (2) is non-zero, the matrix is invertible.

### Step 3: Find the adjugate of the matrix
The adjugate (or adjoint) of the matrix

[tex]\[ \begin{pmatrix} a & b \\ c & d \end{pmatrix} \][/tex]

is computed by swapping the elements on the main diagonal and changing the sign of the off-diagonal elements:

[tex]\[ \text{adj} \begin{pmatrix} a & b \\ c & d \end{pmatrix} = \begin{pmatrix} d & -b \\ -c & a \end{pmatrix}. \][/tex]

Applying this to our matrix:

[tex]\[ \begin{pmatrix} 2 & 0 \\ 9 & 1 \end{pmatrix} , \][/tex]

the adjugate matrix is:

[tex]\[ \begin{pmatrix} 1 & -0 \\ -9 & 2 \end{pmatrix} = \begin{pmatrix} 1 & 0 \\ -9 & 2 \end{pmatrix}. \][/tex]

### Step 4: Calculate the inverse
The inverse of a matrix

[tex]\[ \begin{pmatrix} a & b \\ c & d \end{pmatrix} \][/tex]

is given by

[tex]\[ \text{inverse} = \frac{1}{\text{det}} \begin{pmatrix} d & -b \\ -c & a \end{pmatrix}. \][/tex]

For our matrix, this becomes:

[tex]\[ \text{inverse} = \frac{1}{2} \begin{pmatrix} 1 & 0 \\ -9 & 2 \end{pmatrix} = \begin{pmatrix} \frac{1}{2} & 0 \\ -\frac{9}{2} & 1 \end{pmatrix} = \begin{pmatrix} 0.5 & 0 \\ -4.5 & 1 \end{pmatrix}. \][/tex]

Thus, the inverse of the matrix

[tex]\[ \begin{pmatrix} 2 & 0 \\ 9 & 1 \end{pmatrix} \][/tex]

is

[tex]\[ \begin{pmatrix} 0.5 & 0 \\ -4.5 & 1 \end{pmatrix}. \][/tex]

### Step 5: Rounding (if necessary)
In this case, the matrix elements are already precise to the hundredth place, so no additional rounding is necessary.

Therefore, the inverse of the given matrix is

[tex]\[ \begin{pmatrix} 0.5 & 0 \\ -4.5 & 1 \end{pmatrix}. \][/tex]
We appreciate your time. Please come back anytime for the latest information and answers to your questions. We hope you found this helpful. Feel free to come back anytime for more accurate answers and updated information. Get the answers you need at Westonci.ca. Stay informed by returning for our latest expert advice.