## is this a diagonal matrix

diagonal matrix is a matrix with each element is0 excep for elements on the major diagonal.

so, does it mean that

( 2 0 0
0 0 0
0 0 3 )

is not a diagonal matrix??
 Recognitions: Gold Member Science Advisor Staff Emeritus A (square) matrix is diagonal iff the nondiagonal entries are zero. The diagonal entries are permitted to be zero as well, so this matrix is diagonal, with diagonal entires 2, 0, and 3: $$\left( \begin{array}{ccc} 2&0&0 \\ 0&0&0 \\ 0&0&3 \end{array} \right)$$ (Yes, I am using this post as an excuse to get more practice writing in LaTeX. [:)])
 Recognitions: Gold Member Science Advisor Staff Emeritus To extend Hurkyl's answer, the conditional in the Hurkyl's definition is: " the nondiagonal entries are zero". That says nothing about numbers on the diagonal which may be zero or non-zero, Your statement: "each element is 0 except for elements on the major diagonal." is a slightly ambiguous way of saying the same thing. The ambiguity could be removed by saying: "each element is 0 except possibly for elements on the major diagonal."

## is this a diagonal matrix

all righttt.. thank you.