# Main diagonal

In linear algebra, the main diagonal of a square matrix is the diagonal which runs from the top left corner to the bottom right corner. For example, the following matrix has 1s down its main diagonal:

[itex]\begin{bmatrix}

1 & 0 & 0\\ 0 & 1 & 0\\ 0 & 0 & 1\end{bmatrix}[itex]

A matrix like the above in which only the elements of the main diagonal are non-zero is called a diagonal matrix. The sum of the entries on the main diagonal of a matrix is known as the trace of that matrix.de:Diagonale (Lineare Algebra) fr:Diagonale principale he:אלכסון ראשי nl:Hoofddiagonaal pl:Przekątna macierzy

• Art and Cultures
• Countries of the World (http://www.academickids.com/encyclopedia/index.php/Countries)
• Space and Astronomy