1. ## compute det A

what is $(-1)^1$
and $(-1)^0$ ?

2. ## Re: compute det A

not sure if image clear
it was in preview

3. ## Re: compute det A

Originally Posted by bigwave
not sure if image clear
it was in preview
Anyone in her/his right mind would expand along the third row:
$2\left| {\begin{array}{*{20}{c}} 1&0 \\ 2&{ - 1} \end{array}} \right|$

See here.

4. ## Re: compute det A

Originally Posted by bigwave

what is $(-1)^1$
and $(-1)^0$ ?
The first example has a (-1)^1 included because the 2nd and 3rd rows were interchanged. The second example didn't move the rows around.

-Dan

5. ## Re: compute det A

Originally Posted by bigwave
what is $(-1)^1$
and $(-1)^0$ ?
Any number, a, to the power 1 is itself, a. Any number, other than 0, to the power 0 is 1.

so $(-1)^1= -1$ and $(-1)^0= 1$.