# Math Help (Matrix Stuff)

Discussion in 'Technical Discussion' started by saxman, Jun 4, 2011.

1. ### saxman

Oldbie Tech Member
Augmented matrix:

[ 008, 004, 002, 001, 4 ]
[ 027, 009, 003, 001, 5 ]
[ 216, 036, 006, 001, 7 ]
[ 512, 064, 008, 001, 4 ]

Linear system:

A(008) + B(004) + C(002) + D = 4
A(027) + B(009) + C(003) + D = 5
A(216) + B(036) + C(006) + D = 7
A(512) + B(064) + C(008) + D = 4

I'm trying to solve for A, B, C, and D. It's been a long, long time since I've done this kind of thing. Can anyone help?

2. ### Synergy

Member
Sounds like you're after <a href="http://en.wikipedia.org/wiki/Gaussian_elimination" target="_blank">Gaussian elimination</a>?

"I'm a superdog!" Member
Code (Text):
1. [&nbsp;&nbsp;0,&nbsp;&nbsp; 0,&nbsp;&nbsp; 0,&nbsp;&nbsp;60, 216]
2. [&nbsp;&nbsp;0,&nbsp;&nbsp; 0, 120,&nbsp;&nbsp; 0, -82]
3. [&nbsp;&nbsp;0, 120,&nbsp;&nbsp; 0,&nbsp;&nbsp; 0,&nbsp;&nbsp;67]
4. [120,&nbsp;&nbsp; 0,&nbsp;&nbsp; 0,&nbsp;&nbsp; 0,&nbsp;&nbsp;-7]
...is what I got from reduced-row-echelon form, outside of the fact that the rows are kind of in reverse order and are weighted by multiples of 60.

Code (Text):
1. [&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0, -7/120]
2. [&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0, 67/120]
3. [&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0, -41/60]
4. [&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1,&nbsp;&nbsp; 18/5]
Eliminates those issues.