Finite Math Help

[Black Yaris]

Anyone familiar with the Echelon or GAUSS-JORDAN method of solving a linear system? My textbook sux, poor examples, and my professor's computer is down and she is using the library computer and I do not have a chance to comunicate with her tonight
4x- y+3z=-2
3x+5y- z=15
-2x+y+ 4z=14
:iono:
there is the first problem... I am stumped.....

[joey1320]

you can check this website http://aspire.cs.uah.edu/textbook/gauss.html

i made it into college calculus but that was 5+ years ago and i have completely forgoten it all. man i gotta hit the textbooks again and sharpen up!

good luck man.

[nsmitchell]

Zing - right over my head!

[ChinoCharles]

I tried for all of five minutes to figure it out, but it has been a looooong time. Sorry buddy. Don't you have to subtract entire equations from one another? Or solve for one variable and go from there? Something like that.

[nsmitchell]

I think Apples have graphical calculators that might be able to digest that stuff...

[DMart]

if u have a ti-83 graphing calculator i believe it'll solve it for you if you put it in the matrices

[static808]

alright, if you wanna actually know the steps that i took, here goes:
1) multiply row 1 by 3, row 2 by -4 and row 3 by 6.
2) row 1 + row 2 = new row 2
3) row 1 + row 3 = new row 3
4) multiply row 1 by -23, row 2 by 3, row 3 by 23.
5) row 1 + row 2 = new row 1
6) row 2 + row 3 = new row 3
7) your 3rd row should now look like: 798z = 1596, OR z = 2.
8) solve backwards from there.

repeat this logic for every problem, and you should be peachy keen. i miss this stuff... but i'll gladly give it up to change diapers and raise my kids right...

--B

[static808]

or you can simply use this page:

http://mkaz.com/math/js_lalg3.html

but be forewarned, you still have to learn how to do it. just use the webpage for homework "help"...

--B

[Black Yaris]

alright, if you wanna actually know the steps that i took, here goes:
1) multiply row 1 by 3, row 2 by -4 and row 3 by 6.
2) row 1 + row 2 = new row 2
3) row 1 + row 3 = new row 3
4) multiply row 1 by -23, row 2 by 3, row 3 by 23.
5) row 1 + row 2 = new row 1
6) row 2 + row 3 = new row 3
7) your 3rd row should now look like: 798z = 1596, OR z = 2.
8) solve backwards from there.

repeat this logic for every problem, and you should be peachy keen. i miss this stuff... but i'll gladly give it up to change diapers and raise my kids right...

--B

life saver:bow: that sample should be in our book

[nqd]

alright, if you wanna actually know the steps that i took, here goes:
1) multiply row 1 by 3, row 2 by -4 and row 3 by 6.
2) row 1 + row 2 = new row 2
3) row 1 + row 3 = new row 3
4) multiply row 1 by -23, row 2 by 3, row 3 by 23.
5) row 1 + row 2 = new row 1
6) row 2 + row 3 = new row 3
7) your 3rd row should now look like: 798z = 1596, OR z = 2.
8) solve backwards from there.

repeat this logic for every problem, and you should be peachy keen. i miss this stuff... but i'll gladly give it up to change diapers and raise my kids right...

--B


dude i can do that in 2 min.....haha yea right!

[redyaris]

Anyone familiar with the Echelon or GAUSS-JORDAN method of solving a linear system? My textbook sux, poor examples, and my professor's computer is down and she is using the library computer and I do not have a chance to comunicate with her tonight
4x- y+3z=-2
3x+5y- z=15
-2x+y+ 4z=14
:iono:
there is the first problem... I am stumped.....

You can do math? Will wonders never cease.

[ChinoCharles]

You can do math? Will wonders never cease.

:laugh: Damn man.

[static808]

life saver:bow: that sample should be in our book

dude, anytime buddy. remember, at the very beginning you can also switch around the equations (1st with the 3rd, 2nd with the 1st, etc...) without affecting the results. why do this?? to get smaller common multiples, so your numbers arent so huge at the end... good luck!

--B

[xed]

42

[ChinoCharles]

static808 is the real deal!

[sherryberry]

wow.. i am just starting to remember this....... I took AP Calc in high school but uhh i don't want to remember this...

[Black Yaris]

I took calc as well, but never learned this

[sherryberry]

well we only did like a lil bit of it. i had a teacher who was like... in love with math...

[landrym28]

I remember doing stuff like this in first year University math. I remember doing it, I just couldn't remember how to do it - since that was probably 7 years ago. :tongue:

[Black Yaris]

how about Solving a system of equations by using the inverse of the coefficient matrix.... I am soooo lost I do not understand the gauss-jordan method at all

[blueskana]

Way to come thru for a brother static808. Nice.

[static808]

how about Solving a system of equations by using the inverse of the coefficient matrix.... I am soooo lost I do not understand the gauss-jordan method at all

solving a system using inverse matrices is very effective, especially if you are very adept at finding determinants AND gaussian elimination is something that you just cant seem to master. however, for systems beyond 3x3, there is no formula for finding inverse matrices, meaning you'll have to use gaussian elimination to actually FIND the inverse matrix. meaning you are once again using a method you were trying to AVOID. if you are sure that your test will only have systems of 3x3 or smaller, then the inverse matrix method of solving systems will be very effective (i know, since i primarily used that method as well!). good luck!

--B

[Black Yaris]

It looks as if all of our problems will be no larger than a 3x3..... I just skipped all the inverse matrices problems on my homework, I hate our text all it shows is the problem and the answer, and it says use row funtions to get the answer, but it does not show you step by step... and everyone is lost in this class

[static808]

It looks as if all of our problems will be no larger than a 3x3.....

then by all means use the inverse matrix method! the only snag with this method is that sometimes you can get nasty fractions, but i'd still rather deal with that than gaussian elimination, where mistakes are more easily made. if you need more help, i can try, but this might be difficult to explain over the internet, seeing as how some of my previous students had a hard time learning this with me right beside them! again, good luck!!

--B

[sam07yaris]

row echelon form

aren't you supposed to make the -2 to a positive

[sam07yaris]

its easy, just let me re teach myself the row echelon form

[cm07yaris]

i <3 math