Question

How do you find the determinant of `|(-6,5),(0,-8)|`?

Answer 1

`abs((-6,5),(0,-8)) = 48`

Explanation:

The determinant of a `2xx2` square matrix is given by the formula:

`abs((a,b),(c,d)) = ad-bc`

So in our example:

`abs((-6,5),(0,-8)) = (-6)(-8)-(5)(0) = 48-0 = 48`

More generally, if `M` is any upper or lower triangular matrix, then its determinant is the product of the main diagonal.

So we could have just written:

`abs((-6,5),(0,-8)) = (-6)(-8) = 48`