Crash Posted April 12, 2005 Share Posted April 12, 2005 Part of my course im doing at the moment is looking at how to determine the inverse of a matrix but i just cant seem to get it, could someone explain how this is done, not in the ways by reducing the to an identity (as i know how to do this) but the proper way where a colomn and a row are deleted.......and something could someone explain this in lamens to me pls? Heres a Matrix to use as an example C=(1 5 3,4 4 3,2 1 1) Link to comment Share on other sites More sharing options...
Dave Posted April 12, 2005 Share Posted April 12, 2005 I think you're thinking of a method used to calculate the deteminant of a matrix. Inverses of matrices are done fairly easily by row reduction. Determinants are just as easy with the method you describe - I can go into it if you want. Link to comment Share on other sites More sharing options...
Crash Posted April 12, 2005 Author Share Posted April 12, 2005 yes please that would be much appreciated Link to comment Share on other sites More sharing options...
Crash Posted April 13, 2005 Author Share Posted April 13, 2005 Is the inverse of a matrix just one over the determinant times the transpose of the matrix? Link to comment Share on other sites More sharing options...
Dapthar Posted April 13, 2005 Share Posted April 13, 2005 Is the inverse of a matrix just one over the determinant times the transpose of the matrix?Nope. Here's a nice introduction to matrix inversion methods. Link: http://home.earthlink.net/~jimlux/radio/math/matinv.htm Link to comment Share on other sites More sharing options...
Crash Posted April 14, 2005 Author Share Posted April 14, 2005 Ok so i got the inverse down real good now thanks, but i dont quite know what is meant by finding the solutions of a homogenous equation (find the null vectors) is that when i put the identity next to it then work through and find a matrix that will give general solution or is that when you solve for Ax=0 and then find the non trivial solutions? Link to comment Share on other sites More sharing options...
Dapthar Posted April 14, 2005 Share Posted April 14, 2005 Ok so i got the inverse down real good now thanks' date=' but i dont quite know what is meant by finding the solutions of a homogenous equation (find the null vectors) is that when i put the identity next to it then work through and find a matrix that will give general solution or is that when you solve for Ax=0 and then find the non trivial solutions?[/quote']It's the [math]Ax = 0[/math] one. Link to comment Share on other sites More sharing options...
Crash Posted April 14, 2005 Author Share Posted April 14, 2005 So i put the matrix = to 0 and then just solve for the variables? Link to comment Share on other sites More sharing options...
Dapthar Posted April 14, 2005 Share Posted April 14, 2005 So i put the matrix = to 0 and then just solve for the variables?Yup. The nontrivial solutions are primarily what one's interested in. Link to comment Share on other sites More sharing options...
Crash Posted April 14, 2005 Author Share Posted April 14, 2005 Im just working through and i did not get a trivial solution (ie no x=0) does that mean im doing it wrong? Ive got A=(3 4 7: 0 1 0 2 : 0 1 4 3 : 0) I reduced that to =(3 4 7 : 0 0 -12 -19 : 0 0 0 -5 1/3: 0) that cant be right can it? Do i continue to reduced row echelon form and i will get the trivial solution am i on the right track? Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now