# quick matrix question about zero determinants

• January 12th 2009, 03:01 AM
tsal15
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 :)
• January 12th 2009, 03:07 AM
Moo
Hello,
Quote:

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 (Wink)
• January 12th 2009, 03:23 AM
tsal15
Quote:

Originally Posted by Moo
Hello,

The 4th row is twice the 1st row (Wink)

Thank you, Moo (the cutest angle in the world (Angel)(Tongueout)) ha ha