+0

# ​ Matrix. pt.2

+5
342
1 Jan 15, 2016

#1
+15

7   Det  = [ 5 * 3] - [5 * 2]   = 15 - 10  = 5

8  Det......copy the first two columns again

3   5   2   3   5

5   3   1   5   3

2   4   2   2   4

Multiply down the diagonals and sum the products

[ (3 * 3 * 2) + (5 * 1 * 2) + (2 * 5 * 4)]  =    [ 18 + 10 + 40 ]   =  68

Multiply up the diagonals and sum the products

[ (2 * 3 * 2) + (4 * 1 * 3)  + ( 2 * 5 * 5) ]  =  [ 12 + 12 + 50] =  74

Subtract the second result from the first

Det  = 68 - 74   = - 6   Jan 15, 2016

#1
+15

7   Det  = [ 5 * 3] - [5 * 2]   = 15 - 10  = 5

8  Det......copy the first two columns again

3   5   2   3   5

5   3   1   5   3

2   4   2   2   4

Multiply down the diagonals and sum the products

[ (3 * 3 * 2) + (5 * 1 * 2) + (2 * 5 * 4)]  =    [ 18 + 10 + 40 ]   =  68

Multiply up the diagonals and sum the products

[ (2 * 3 * 2) + (4 * 1 * 3)  + ( 2 * 5 * 5) ]  =  [ 12 + 12 + 50] =  74

Subtract the second result from the first

Det  = 68 - 74   = - 6   CPhill Jan 15, 2016