Linear algebra,

How do I find the determinant of a 4x4 matrix ??

Example https://www.dropbox.com/s/7tf49eu9lhgy9gl/Screenshot%202013-11-18%2011.57.38.jpg

Question

Linear algebra,

How do I find the determinant of a 4x4 matrix ??

Example https://www.dropbox.com/s/7tf49eu9lhgy9gl/Screenshot%202013-11-18%2011.57.38.jpg

christos · Answer

@hartnn do you know ?

kainui · Answer

So the determinant is found the same way for everything once you know the method. You pick a row or column, any one you want, preferably the one with the most 0's in it. And you go about using each one as the coefficient of the smaller matrices as determinants. So maybe if I make an example it'll be simpler.

|dw:1384769839394:dw|

So in this example, I turned a 4x4 into a bunch of 3x3's. I picked the second row, I could have easily chosen a column or any other row. But whatever you choose, make sure you put the proper sign on them, + or - depending on where it is. Now you see why you should choose the row or column with the most 0's.

kainui · Answer

So as you go across, you cut out everything in the same row and column as that one. So when I made the first one: |dw:1384770237867:dw|