Using Gauss-Jordan to Solve a System of Three Linear Equations - Example 1

[295laanne]

thnx for these simple yet very helpful tutorial...

[theredgear12]

I'm live in Austin, too! I might just drop by ACC to for tutoring in the flesh! ;D your videos are splendid

[patrickJMT]

@theredgear12 good luck with acc, i have not been there for years now :) only a brief stop at that place for me!

[theredgear12]

@patrickJMT I actually go to UT :) but thanks anyway! so you do YouTube math videos for a living now...?

[theredgear12]

@patrickJMT and please excuse my dear aunt sally, jk, my grammar -_-

[TheIcrumble]

thank you!

you got nice hand btw :))))

[trez32]

can I use this gauss jordan system with other matrix than 3x3 dimensions but still square?

[persiantube1990]

@patrickJMT so this is LU decomposition?

[tRGodzApostle]

ughh this subject is legitimetly more difficult than calc 2, much more tedious imo

[McChickenn]

@tRGodzApostle

No doubt man. I just finished calc 2, and it was ten times easier than this horse shit

[ilovecandy161]

SALAMAT

[cantcount0]

wow that's just kinda simple, thanks. i dont know why in books they use all these complicated annotations that confuse the heck out of you!

[Republic1ders]

Thanks for making my 2 grueling weeks of matrices easier =)

[MicNarcolepsy]

I see I'm not the only one who messes up with the clip of a sharpie! Haha!

[macoglesby]

my teacher told us that your are not supposed to subtract or divide when solving these, but you can multiply by fractions. Why can we not divide and why did you divide by five?

[patrickJMT]

@macoglesby dunno, you would have to ask your teacher. you can 100% divide a row by any non zero number, no problem.

[patrickJMT]

@macoglesby it could be the desire to avoid fractions, which kill many people

[TheExtinctSpecie]

@patrickJMT I think he is thinking you shouldn't divide matrices.

[patrickJMT]

@TheExtinctSpecie well, but you can subtract matrices, so i am not sure what he means.

[girlfromipanema972]

@TheExtinctSpecie well but you can multiply them. So if you multiply a matrix with a fraction then you have divided it. There's nothing wrong with that.What you cannot divide is a matrix with a matrix (sorry my math english is not very good,I hope you understood)

[weoyondo]

@macoglesby well, since x/5 = x * 1/5, it should be ok.

[ComputerNerd666]

wow.. i learn almost nothing in my class this 7 min vid.taught me so much :) woooooooooooow these r actuallly interesting haha :D

[VIR092]

The Gauss-Elimination is certainly a captivating and definately an effective of means of matrix calculations, once you get the dynamic of it down it really is a cool tool to have.

[mnthol]

Your Vids are WAY better than Khan's .. no offence .. but YOU ARE AWESOME

[patrickJMT]

@mnthol that does not offend me : )

[mnthol]

@patrickJMT No offence to the guy at Khan .. he saves my ass too :D ..

[patrickJMT]

@mnthol he gets $2,000,000 grants so he is doing something right : )

[rabia0011]

thanx sooo much... this helped a bunch.. i have a midterm tomorow n our math teacher dint taught us s***

[EdithGuOropeza]

i wish mine looked this neat:/ haa

[yinyengz515]

These are easy, its just that its a lot of little steps and one wrong step means that everything is wrong

[swisscheeseMAFIA]

@yinyengz515 wow didnt ask..

[dtm876]

so what is the difference between row reduction method / gaussian elimination / gaussjordan elimination ???!!!!

[bman54950]

i hate having to choose rows to change. i always get these wrong! :P

[patrickJMT]

@bman54950 they do take some practice to get the hang of

[2020nigz]

I didnt have sound and still found this better than my maths teacher!!

[nocome2]

I always just don't know what to do to eliminate the y again during the second equation.

[JLchevz]

I really like your videos patrick :D

[patrickJMT]

@JLchevz thanks : )

[chrismerk420]

@patrickJMT aaawwwkwaaard.....

[FattieAcidProduction]

huh a lot fo math proffs are left handed.. weird..

[brxscooby]

i thought dividing was illegal when dealing with matrices

[mibbzx1493]

@brxscooby thats wat thru me off

[brxscooby]

@mibbzx1493 it looked like it worked though

[patrickJMT]

@brxscooby you can not divide two matrices, but you can divide elements inside of a matrix.

[hunterxhunter007kane]

THX for the help

[nidabilli]

wow it helped thanks :)

[metalman134]

 can you make a vid on solving system equations using gaussian elimination? thankyou :)

[patrickJMT]

@metalman134 is that not what this is? isnt it the same thing

[metalman134]

@patrickJMT no, those are two separate things..

[tonywoy]

@metalman134 gauss elimination is actually simpler. The only difference is you only have to make zeros on the lower left part. In the end though, youve to do a back substitution since you can only obtain x3 directly from the matrix. Does that help?

[JLchevz]

@metalman134 gaussian elimination is simpler, only you only have to have zeros below the diagonal (not below and above like in gauss jordan)

[vd853]

Is this actually faster than solving it the old way? like making x,y,z disappear...

[patrickJMT]

@vd853 for large systems of equations, this is the method to use. easier to teach with 3 equations of course

[MegaBangiz]

why did you enterchange the Y and Z? pls repost ASAP..... because when I was not reinterchange I got fractions..... why? tnx a lot in advance

[lollerskates101LOL]

how is this easier than substitution or the elimination method? I hate using a matrix! :(

[Tinzert]

Ahh too fast for me.

[froet213kil]

emm, is there any advantage of using the gauss jordan method instead of just using the conventional method ie. eliminating some terms?

[021311]

I struggled two hours on a question, and solve it in 10 minutes after watching this video.

[DaDumFriek]

Patrick....you're really awesome. I was stuck on a problem for the longest time after doing calculus for two years and I totally forgot that you could switch rows. That literally saved my life when it came to solving the problem. Thank you very much!

[Canouver]

How come you didn't just solve the equation using Gaussian elimination? When you got it in upper triangular form you immediately know that z = 3, and can deduce the rest of the variables using back substitution.

[redpatito]

You sir just save my life and I thank thee!

[philbot01]

Thanks Patrick!!!

Just letting you know, My name is patrick, I like maths AND i'm left handed too.

We have so much in common!

[patrickJMT]

@philbot01 ha, my long lost twin

[blackfuse27]

@patrickJMT im left handed and i hate math :D

[6cheesy6]

@philbot01 ive had four math teachers in my life and all of them are left handed

[23youwatch]

Patrick, im a lil confused abt how u noe which row to update afta doin an operation.

like-> -3*R2 + R1 = R1.... how do u know its supposed to be R1? and not R2?

pls reply soon!

[patrickJMT]

@23youwatch whatever is on the right side of the equal sign is what gets updated

[ruslangelaev]

do I have to get identity matrix ? or reduced row echelon form is enough? it makes me confused.

[paydog23]

So I want to make sure, are there multiple correct ways of arriving at the same answer?

[patrickJMT]

@paydog23 yep

[paydog23]

@patrickJMT thanks man

[justdnk777]

Wow. This is going to take awhile to get good at. Thanks for the video Patrick.

[patrickJMT]

@justdnk777 it is tedious!!!! and you are welcome.

[birdsofafeather1990]

Thank you for a great video. They still take me a long time to do though, although I assume that's normal because in the past paper we got there was a GJ question worth 12 marks when everything else was worth at most 4.

[xcompa77x]

god bless you for this work you do. you bring peace of mind and confidence to so many. you shall be rewarded for it i know it. right this moment i am cramming for a test and maybe i won't fail my college algebra. my prof was taught by a nobel prize winner for his doctorate in math and he drives me crazy. they should give people like you the prize you are better. keep making vids!!!

[OxMATHEMATICS]

Too Good You Are

But show your face i wanna see you:-)

[patrickJMT]

@OxMATHEMATICS profile page is me!

[tiongbo]

you are my idol.

[lilmaqi]

Thank you!

[patrickJMT]

@lilmaqi no problem!

[Waranle]

Thank you Patrick :)

[patrickJMT]

@Waranle you are very welcome waranle. hope all is well for you!

[Waranle]

@patrickJMT everything is ok, thank you

[schlynn]

Isn't it easier and fast to get the matrix into upper echelon form? Then use back substitution to solve?

[patrickJMT]

@schlynn well, lots of ways to do lots of things. i think it would probably take me about the same amount of time either way.