Find the inverse of the following matrix A, if possible. Check that AA^(-1)=I and A^(-1)A=I A=[[7,4],[7,7]] The inverse, A^(-1) is?

Damien Horton

Damien Horton

Answered question

2022-07-31

Find the inverse of the following matrix A, if possible. Check that A A 1 = I and A 1 A = I
A = [ 7 4 7 7 ]
The inverse, A 1 is ?

Answer & Explanation

Izabelle Frost

Izabelle Frost

Beginner2022-08-01Added 13 answers

1 a b b c [ d b c a ]
1 49 28 [ 7 4 7 7 ]
Answer:
[ 1 / 3 4 / 21 1 / 3 1 / 3 ]
Elisabeth Esparza

Elisabeth Esparza

Beginner2022-08-02Added 1 answers

A = [ 7 4 7 7 ] ,   f i n d   A 1 .
Inverse of a 2 × 2 matrix:
If A = [ a b c d ]   t h e n   A 1 = 1 a d b c [ d b c a ] . If ad-bc=0, then A has no inverse.
So, A 1 = 1 7 7 4 7 [ 7 4 7 7 ] = 1 21 [ 7 4 7 7 ] = [ 7 21 4 21 7 21 7 21 ] = [ 1 3 4 21 1 3 1 3 ]

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