How do we get symmetric matrix ?

by Kardi Teknomo

Suppose we have a integer matrix , to get symmetric matrix from , we multiply matrix by its transpose: or . . Here is how to do it in Excel. You may download the spreadsheet example here.

1. Type any matrix 3 by 3. Suppose our matrix is like this figure on the right
2. Note that optionally you can give name to the matrix using menu Insert-Name-Define matrix_N, then press OK button.
3. In other cell, type =TRANSPOSE(matrix_N), where the array is the 3 by 3 matrix N. Then press enter key.
4. Don't worry about the result yet. Starting from the cell with Transpose formula, highlight 3 by 3 cells. Press F2, and it will be appear like the following figure . Then press CTRL-SHIFT-ENTER together. You get the transpose matrix . Optionally you may give name matrix_N1 to the transpose matrix by using procedure in step 2 above.
5. Now you can get the symmetric matrix by multiplying multiply matrix by its transpose. In a new empty cell type = MMULT(matrix_N1, matrix_N) and then press enter key.
6. Starting with the cell with MMult formula, highlight 3 by 3 cells. Press F2, and it will be appear like the following figure Then press CTRL-SHIFT-ENTER together you get the symmetric matrix as shown in the figure below

The spreadsheet example can be downloaded here.

See also: Goal Seek Tutorial, MS Excel Tutorial index, Kardi Teknomo's Tutorial

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Teknomo, Kardi. How do we get symmetric matrix ?. http:\\people.revoledu.com\kardi\ tutorial\Excel\SymmetricMatrix.html