Question

Linear Algebra,

Why AA^-1 = Identity matrix ?

Answer 1

yup, under the condition that A is invertible

Answer 2

I thought AA^-1 = 1 ? or its wrong ?

Answer 3

1 is a number, how can a matrix = a number?

Answer 4

\(\mathrm{I} = [1]\) where [1] is the diagonal matrix with only 1s in it. Also, if you use the Matrix Inverse Algorithm you can see the relationship between the inverse and the matrix and the identity.
http://www.proofwiki.org/wiki/Matrix_Inverse_Algorithm