When can we say a matrix is invertible?

Asked by Jogy Jacob | 5th Apr, 2013, 10:01: AM

Expert Answer:

1. An n x n matrix A is called invertible if there exists an n x n matrix B such that AB = BA = I. In this case, B is called the inverse of A. A can only have an inverse if it is an n x n (square) matrix and the its determinant is not equal to 0. 
 
2. In the above case, A would be the invertible marix i.e. the matrix of which inverse can be calculated and B would be the corresponding inverse matrix, i.e the matrix which is inverse of the invertible matrix. 
 
3. Inverse of a matrix A = 1/determinant(A) * adj (A)

Answered by  | 5th Apr, 2013, 04:51: PM

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