# Inverse of a Matrix

1. Jan 16, 2008

### nanoWatt

Hi,

I'm taking a Calculus I class, so they won't be going into Matrices very much. That's more for Linear Algebra.

I'm going through an E&M book now (as a refresher from my Physics days of 7 years ago). This book assumes knowledge in getting the inverse of a matrix.

Using this site, I was able to find the inverse, by using row reduction. However, I was wondering if there is a quicker or easier way to find a matrix inverse.

http://people.hofstra.edu/Stefan_waner/RealWorld/tutorialsf1/frames3_3.html [Broken]

Last edited by a moderator: May 3, 2017
2. Jan 16, 2008

### EnumaElish

3. Jan 16, 2008

### ObsessiveMathsFreak

Be aware that finding the inverse can be a very long and laborious task. In fact, much of the time this is simply not done, and the inverse is either estimated, which can be done fairly easily to a reasonable degree of accuracy, or else ways around getting the inverse are used, e.g. gauss elimination followed by back substitution.

4. Jan 16, 2008

### HallsofIvy

There are a number of different ways of finding an inverse matrix. In my opinion, "row reduction" is the simplest.

5. Jan 16, 2008

### jdavel

Another way is to use the fact that the inverse of A is the transpose of the matrix of cofactors of A divided by the determinant of A. Probably more calculations than row reduction, but I find it easier to remember. And for a given size matrix, it's pretty easy to program in Excel.