Question

Calcule o determinante

a) [2 5]
[4 1] =

b)[0 -1 3]
[2 1 4] =
[-1 2 -2]

c) [2 3 -1]
[1 -2 0] =
[3 1 2]

Answer 1

a)
| 2. 5 |
| 4. 1 |

= (2 x 1) - (4 x 1)
= 2 - 4
= - 2

b)
| 0. -1. 3 |0. -1.
| 2. 1 ..4 |2... 1
| -1. 2 -2 |-1 ..2

=(0x1x2)+(-1x4x-1)+(3x2x2)-(-1x3x2)-(-1x4x-1)-(3x2x2)

= 0+ 4 + 12- (-6)-4-12

= 4 + 12 + 6 - 4 - 12

= 16 + 6 - 4 - 12

= 32 - 4 - 12

= 28 - 12

= 16

c.-)
| 2...3...-1 |2...3
| 1....-2...0|1...-2
| 3....1.....2|3...1

=(2x-2x2)+(3x0x3)+(-1x1x1)-(3x-2x-1)-(1x0x2)-(2x1x3)

= - 4 + 0 + (-1) - 6 - 0 - 6

= - 4 + 0 - 1 - 6 - 0 - 6

= - 4 - 1 - 6 - 0 - 6

= -5 - 6 - 0 - 6

= -11 - 0 - 6

= - 11 - 6

= - 17