 Hello and welcome to this session. In this session, we discussed the following question which says if matrix A is equal to 1, 2, 3, which are the elements in one row of the matrix A, write A A dash, where A dash is the transpose of matrix A. Now we know if we have a matrix A equal to A ij, that is the elements are A ij of order m by n, then its transpose is given by A dash which is equal to the matrix with elements A ji of order n by n. That is the transpose of the matrix is obtained by interchanging the rows and columns of the given matrix. This is the key idea that we use for this question. Let's proceed with the solution now. We are given a matrix A equal to 1, 2, 3, elements in the row of the matrix A. This matrix A has one row and three columns and the elements of the row are 1, 2 and 3. Now let's find out A dash that is the transpose of the matrix A which is obtained by interchanging the rows and columns of the given matrix A and so this would be equal to 1, 2 and 3 in a column. So this is the transpose of the given matrix A. Now A A dash is equal to the matrix A with elements 1, 2 and 3 in a row multiplied by A dash which is the matrix 1, 2, 3 that is its elements are 1, 2, 3 in a column. Thus we have A A dash is equal to the matrix with element 1 multiplied by 1 plus 2 multiplied by 2 plus 3 multiplied by 3 and so this is equal to the matrix with element 1 plus 4 plus 9 which is equal to 14. So we have A A dash is equal to matrix with element 14. So this is our final answer. This completes the session. Hope you have understood the solution of this question.