determinan dan invers 3*3

( 1 2 3 )
( 1 3 4 )
( 1 4 3 )

Jawab :
| 1 2 3 | 1 2
| 1 3 4 | 1 3
| 1 4 3 | 1 4

Det A = aei+bfg+cdh-ceg-afh-bdi
=1.3.3+2.4.1+3.1.4-3.3.1-1.4.4-2.1.3
=9+8+12-9-16-6
=17+12-25-6
=29-31
=-2

Invers : Ordo 3x3 Memiliki Invers sebab memiliki Kolom dan Baris Sama

Matrix Determinant.

Use Sarrus rule to solve this problem!
[tex]\displaystyle \begin{vmatrix} 1 &2 & 3\\ 1&3 & 4\\ 1 &4 & 3 \end{vmatrix}= \begin{vmatrix} 1 &2 & 3\\ 1&3 & 4\\ 1 &4 & 3 \end{vmatrix}\begin{matrix} 1 &2 \\ 1 & 3\\ 1 & 4 \end{matrix}[/tex]
det = 1(3)(3) + 2(4)(1) + 3(1)(4) - 1(3)(3) - 4(4)(1) - 3(1)(2)
      = 9 + 8 + 12 - 9 - 16 - 6
      = -2