SOLUTION: I am having trouble finding the determinant of the matrix [-1 2] [1 3] with the 1 and 3 directly under the -1 and 2, with one set of []. Any help is greatly appreciated. Than

Algebra ->  Matrices-and-determiminant -> SOLUTION: I am having trouble finding the determinant of the matrix [-1 2] [1 3] with the 1 and 3 directly under the -1 and 2, with one set of []. Any help is greatly appreciated. Than      Log On


   

Question 84137: I am having trouble finding the determinant of the matrix [-1 2] [1 3] with the 1 and 3 directly under the -1 and 2, with one set of []. Any help is greatly appreciated.
Thank you!
Found 2 solutions by venugopalramana, jim_thompson5910:
Answer by venugopalramana(3286) About Me  (Show Source):
You can put this solution on YOUR website!
I am having trouble finding the determinant of the matrix [-1 2] [1 3] with the 1 and 3 directly under the -1 and 2, with one set of []. Any help is greatly appreciated.
Thank you!
-1,2
1,3
DETERMINANT =
(-1)(3)-(2)(1)=-3-2=-5

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
If you have a general 2x2 matrix

%0D%0A%28%0D%0A++matrix%282%2C2%2C+%0D%0A+++a%2C+b%2C+%0D%0A++++c%2C+d+%29%0D%0A%29%0D%0A
the determinant of that matrix is
a%2Ad-b%2Ac

So if we have this matrix
%0D%0A%28%0D%0A++matrix%282%2C2%2C+%0D%0A+++-1%2C+2%2C+%0D%0A++++1%2C+3+%29%0D%0A%29%0D%0A

the determinant is

-1%2A3-2%2A1=-3-2=-5

So the determinant is -5