what is transpose in a matrix. explain with the simplest example
The transpose of a matrix is a new matrix obtained by flipping the original matrix over its diagonal. This means that the rows of the original matrix become the columns of the transposed matrix and vice versa.
### Definition
If you have a matrix \( A \) with elements \( a_{ij} \), where \( i \) is the row index and \( j \) is the column index, the transpose of matrix \( A \), denoted as \( A^T \) or \( A' \), is defined as:
\[
(A^T)_{ij} = A_{ji}
\]
### Simple Example
Let's consider a simple \( 2 \times 3 \) matrix \( A \):
\[
A = \begin{pmatrix}
1 & 2 & 3 \\
4 & 5 & 6
\end{pmatrix}
\]
Here, matrix \( A \) has 2 rows and 3 columns.
To find the transpose \( A^T \), we swap the rows and columns:
The first row of \( A \) (which is \( (1, 2, 3) \)) becomes the first column of \( A^T \). The second row of \( A \) (which is \( (4, 5, 6) \)) becomes the second column of \( A^T \).
Thus, the transposed matrix \( A^T \) will be a \( 3 \times 2 \) matrix:
\[
A^T = \begin{pmatrix}
1 & 4 \\
2 & 5 \\
3 & 6
\end{pmatrix}
\]
### Summary
In summary, the transposition of a matrix involves converting rows into columns and vice versa. In our example, a \( 2 \times 3 \) matrix became a \( 3 \times 2 \) matrix after transposition.