Question

Sejam as matrizes A=
[-1 0 1]
[0 2 -2]
e B=
[ 2 -1]
[ 1 2]
[ 0 1]
O determinante da matriz A×B é :
a)64
b)8
c)0
d)-8
e)-64

Answer 1

Resposta:

d) -8

Explicação passo a passo:

$AB=\left[\begin{array}{ccc}-1&0&1\\0&2&-2\end{array}\right]\left[\begin{array}{ccc}2&-1\\1&2\\0&1\end{array}\right]=\left[\begin{array}{cc}-2&2\\2&2\end{array}\right]\\\\det(AB) = (-2)\cdot2-2\cdot2=-4-4=-8$

Answer 2

Resposta:

A=

[-1 0 1]

[0 2 -2]

B=

[ 2 -1]

[ 1 2]

[ 0 1]

AxB

-1 *2+0*1+1*0 =-2    -1 *(-1)+0*2+1*1= 2

0 *2+2*1-2*0 =  2    0 *(-1)+2*2-2*1= 2

=

-2    2

2     2

det(A*B) = -2*2-2*2 = -4-4 =-8

Letra D