Question

find a matrix M(2x2) such that AM=I. I is a identity matrix of 2x2.

Answer 1

\[M=A^{-1}\]

Answer 2

what is A here

Answer 3

A=[7 9; 3 4] sorry for the dealy. I lost internet connection. So how do I get A^ -1

Answer 4

Does that mean the inverse of a matrix?

Answer 5

yh inverse only

Answer 6

how do I found it? (1/det(A))*A?

Answer 7

coz the determinant is equal to 1

Answer 8

adj A / determinant A

Answer 9

determinant of A is -1

Answer 10

=> 4 -9
-3 7

Answer 11

yeah. So det(A)=(28)-(27) =1

Answer 12

that means that M must be equal to A.

Answer 13

no...
M= adjoint of A

Answer 14

what is adjoint?

Answer 15

and sorry the original matrix A ={{7,9},{3,4}}

Answer 16

yh i took A as this only....

Answer 17

adjoint: adjoint of a matrix , can be got by replacing each element of a matrix, by its cofactor..

Answer 18

so you mena I should change ij by ji in the matrix

Answer 19

NO.
i.e transpose... i said cofactor...

Answer 20

can you give me an example man. Lets use this matrix K={{1,2}, {3,4}}

Answer 21

its adjoint is...
4 -2
-3 1

Answer 22

how did you get that?

Answer 23

I dont get it. Sorry

Answer 24

Doing some research I finally got with the answer. Thanks Kishan