# Math Help - quick matrix question about zero determinants

1. ## quick matrix question about zero determinants

Ok so I know that the following matrix has a determinant of zero, which means it has no inverse matrix because I found out that it has a row of zeros... But, just by looking at it, how can I tell its determinant is zero?

$\begin{bmatrix} 0 & 0 & 1 & 0 \\ 0 & 1 & 0 & 0 \\ 1 & 0 & 0 & 2\\ 0 & 0 & 2 & 0 \end{bmatrix}$

Thank you

2. Hello,
Originally Posted by tsal15
Ok so I know that the following matrix has a determinant of zero, which means it has no inverse matrix because I found out that it has a row of zeros... But, just by looking at it, how can I tell its determinant is zero?

$\begin{bmatrix} 0 & 0 & 1 & 0 \\ 0 & 1 & 0 & 0 \\ 1 & 0 & 0 & 2\\ 0 & 0 & 2 & 0 \end{bmatrix}$

Thank you
The 4th row is twice the 1st row

3. Originally Posted by Moo
Hello,

The 4th row is twice the 1st row
Thank you, Moo (the cutest angle in the world ) ha ha