An introduction to generalized inverse of matrices and their properties

A Matrix has an inverse only if it is a square and even then only if it is non singular. Usually singular and rectangular matrices do not posses inverse. In recent years needs have been felt in numerous areas of applied mathematics for some kind of partial inverse of matrix that is singular or even rectangular. Such inverse are called generalized inverse. The concept of generalized inverse was introduced first by Moore in 1920 and independently re discovered by Penrose in 1955.