Chapter Summary. 3- Matrices
2
Matrices ( a b c d ) ± ( e f g h ) = ( a±e b±f c±g d±h ) ( a b c d )( p q ) = ( ap +bq cp +dq ) ( a b )( p q ) = ( ap +br aq+ bs ) 3 Exampl e 2A – 5B The 2x2 identity matrix is called I, where: I¿ ( 1 0 0 1 ) AB¿ ( 3 4 2 5 )( 2 −1 6 7 ) ¿ ( 3 × 2+4 × 6 3 ×−1+4 × 7 2 × 2+5 × 6 2 ×−1+5 × 7 ) ¿ ( 30 25 34 33 ) ( 2 −1 )( 3 4 ) Find 2A – 5B, where A¿ ( 8 2 ) and B¿ ( 1 −4 ) . Example Find AB and BA where A and B
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Exercises Matrices
Transcript of Chapter Summary. 3- Matrices
Matrices
(a bc d )±(e f
g h)=(a±e b± fc± g d±h)
(a bc d )( pq )=(ap+bqcp+dq )
(a bc d )( p q
r s )=(ap+br aq+bscp+dr cq+ds)
3
2A – 5B¿2(82)−5( 1−4) ¿(164 )−( 5−20) ¿(1124)
Example
The 2x2 identity matrix is called I, where:
I¿(1 00 1)
When a matrix is multiplied by the identity matrix I, it stays the same.
Find 2A – 5B, where A¿(82) and B¿( 1−4).
AB¿(3 42 5)(2 −1
6 7 ) ¿(3×2+4×6 3×−1+4×7
2×2+5×6 2×−1+5×7 ) ¿(30 25
34 33)BA¿(2 −1
6 7 )(3 42 5 )
Find AB and BA where A¿(3 42 5) and B¿(2 −1
6 7 )
Example