How do you find the determinant of a 2x2 matrix?

Question

lalaly · Answer

if you have 

a   b
c    d

the determinant of that is a*b-c*d

anonymous · Answer

so if the matrix is (0      1)  then what would the determinant be?
                          (-4 -12)

lalaly · Answer

(0*12)-(1*-4)= 4

lalaly · Answer

its -12.... sorry for the mistake,,,,but still it has the same answer since its multiplied by 0

anonymous · Answer

cool :) thanks!

anonymous · Answer

hey! but don't you have to do 1/ad-bc ?

lalaly · Answer

thts not the determinant ,, that is when you find the inverse of the matrix

anonymous · Answer

ohh. okay

lalaly · Answer

if the matrix is (a   b)
                     (c    d)
the inverse of the matrix is
1/ad-bc multiplied by the transpose of the matrix which is (d   -b)
                                                                                      (-c    a)
"ad-bc" is the determinant here only
and for the transpose you just switch a and d then change the signs of b nd c

anonymous · Answer

4