Solving Matrices...

2008-04-21 11:25:14

#1

tyme414: Member; +29|6660

Could use a little help solving this problem right here. The first box is a 3x3 matrix, and the answers are a 1x3.

| .08w + .09x + .10y | = | 336 |
| -w + 1x + 0y | = | 500 |
| 0w + -3x + 1y | = | 0 |

The answers are:

w = 300
x = 800
y = 2400

Just need a little help on seeing why. Thanks in advance.

2008-04-21 12:02:40

#2

kylef: Gone; +1,352|6512|N. Ireland

I'll try and do this later for you. Although I'll need to get my scanner up because there is no way I am typing it all out! (doing Matrices in Additional Mathematics - May 16 exam, oh no!) Sorry if I don't get it done though

Last edited by kylef (2008-04-21 12:05:41)

2008-04-21 12:05:12

#3

jamiet757: Member; +138|6641

I don't know what the fuck that means.

2008-04-21 12:05:52

#4

Parker: isteal; +1,452|6413|The Gem Saloon

jamiet757 wrote:
I don't know what the fuck that means.

then by all means, fucking post so everyone knows that

2008-04-21 12:12:23

#5

weerdfoo1: Banned; +26|6183|California

| .08 .09 .10 | |w| = | 336 |
| -1 1 0 | |x| = | 500 |
| 0 -3 1 | |y| = | 0 |

AX = B
X = (A^-1)(B)

Where A^-1 is the inverse of the matrix

Inverse of a matrix:
http://math.uww.edu/~mcfarlat/inverse.htm

Kind of a condensed version, but hope this helps

Last edited by weerdfoo1 (2008-04-21 12:13:45)

2008-04-21 12:12:41

#6

tyme414: Member; +29|6660

Well I take the test on thursday, going to try and get some help tonight from a friend. And in case your wondering, no I cant ask the teacher because I was expelled from school and return next Monday after being out for 2 months.

2008-04-21 12:29:31

#7

tyme414: Member; +29|6660

weerdfoo1 wrote:
| .08 .09 .10 | |w| = | 336 |
| -1 1 0 | |x| = | 500 |
| 0 -3 1 | |y| = | 0 |

AX = B
X = (A^-1)(B)

Where A^-1 is the inverse of the matrix

Inverse of a matrix:
http://math.uww.edu/~mcfarlat/inverse.htm

Kind of a condensed version, but hope this helps

Thanks much man, used my calculator to figure it out. [A]-1[b]. Thanks again

2008-04-21 12:32:36

#8

sexecuti0ner: What kinda guy are you are?; +148|6250

tyme414 wrote:
Well I take the test on thursday, going to try and get some help tonight from a friend. And in case your wondering, no I cant ask the teacher because I was expelled from school and return next Monday after being out for 2 months.

what'd you get expelled for?

2008-04-21 12:37:55

#9

tyme414: Member; +29|6660

sexecuti0ner wrote:
tyme414 wrote:
Well I take the test on thursday, going to try and get some help tonight from a friend. And in case your wondering, no I cant ask the teacher because I was expelled from school and return next Monday after being out for 2 months.
what'd you get expelled for?

Technology use violation... don't really want to talk bout what I did. Was quite serious tbh.

2008-04-21 12:40:48

#10

cablecopulate: Member; +449|6756|Massachusetts.

Child porn no doubt.

2008-04-21 12:54:53

#11

kylef: Gone; +1,352|6512|N. Ireland

^ lol. Anyway, remember to find the determinant etc... |A|

Last edited by kylef (2008-04-21 12:55:09)

2008-04-21 13:04:51

#12

tyme414: Member; +29|6660

cablecopulate wrote:
Child porn no doubt.

Probably would have been a suspension for that

2008-04-21 16:54:39

#13

IonYou: Member; +3|6652

Technology use violation? You used technology to cheat? What did you do text classmates using your cellphone for the answers?

2008-04-21 19:04:40

#14

Ryan: Member; +1,230|6861|Alberta, Canada

As my dad would say,

"Get rid of all those letters and add the numbers."

2008-04-21 23:53:48

#15

SharkyMcshark: I'll take two; +132|6804|Perth, Western Australia

I'd have gone the echelon method since we didn't use inverse of 3x3's

2008-04-22 03:48:32

#16

_raab: Member; +28|6252|Western Aust.

Yup, theres 2 ways for this, using the inverse method and just typing it in you're calculator.
eg:
A = | .08 + .09 + .10 | | 336 |
| -1 + 1 + 0 | | 500 |
| 0 + -3 + 1 | | 0 |

B = | 336 |
| 500 |
| 0 |

A^(-1)*B = [w] = [300]
[x] [800]
[y] [2400]

Or as sharky said, using echelon method. Sorry, I can't be fucked doing it, but if you are doing matrices you should be learning echelon form, reduced row echelon form etc. I probably shouldn't be linking you to this site because it does everything for you, but you might learn from it. http://www.math.odu.edu/~bogacki/cgi-bin/lat.cgi

What you are looking for is the "Solving a linear system of equations" or "Transforming a matrix to reduced row echelon form".

And sharky, how come you didn't use inverses of 3x3's? What school/uni did ya go to?

Last edited by _raab (2008-04-22 03:50:58)

BF2S Forums Solving Matrices...

jamiet757 wrote:

weerdfoo1 wrote:

tyme414 wrote:

sexecuti0ner wrote:

tyme414 wrote:

cablecopulate wrote:

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