Matrix help!

1. Oct 27, 2005

elle

I've been asked to solve the following matrix and find the solutions but I'm not sure if I've reached the correct 'end' matrix.

Original matrix:

1 2 -1 3
-1 3 4 10
-1 1 -2 8

The last matrix I got after my calculations:

1 2 -1 3
0 1 1 11/3
0 0 8 26/3

2. Oct 27, 2005

HallsofIvy

What do you mean by "solving" a matrix? I know how to solve equations and I know, more generally, how to solve problems but I don't know what is meant by solving a matrix.
You appear to be row-reducing a matrix to row-echelon form. If so that is certainly not what I get. How about stating exactly what the problem is and showing your work?

3. Oct 27, 2005

elle

oh its okay, I've managed to work out where I went wrong. Sorry for not stating the problem clearly :uhh:

Erm but I have two more questions to ask, and was wondering if anyone can offer me some help or hints. I havent got any working for this because I really do not have any idea how to approach the answer.

Can anyone explain to me what a subspace is? I've got notes on it but I'm confused with all the notation etc. Thanks in advance!

http://tinypic.com/f1mp3b.jpg"

Last edited by a moderator: Apr 21, 2017
4. Oct 27, 2005

hypermorphism

A subspace of a vector space is just a subset of the vectors in the space that are also a vector space. For example, R2 is a 2-dimensional vector space. The set of vectors (x,y) that satisfy the equation y=x is a subspace of R2 but the set of vectors (x,y) that satisfy x2 + y2 = 1 is not.