Inverting Matrices (part 3)

[joasten]

So ifthe top row is (-1 0 0), I can divide it by -1 so it becomes 1?

[nikmuic]

IS THIS MAGIC OR WHAT?!

THANK YOU ARCHWIZARD!

[ringofjews]

thank you o much very help full

[frantzzzze]

Thank you sooooo much :) from 0:00 until 2:27 i already understood everything, but with my maths teacher 3 hours lesson and i didn't understand how it is done...

[missbloodyrose1993]

Can you use this method with any square matrix? Like 4x4, 5x5 etc

[robinjam304]

My matrices are augmented.

[aberforthsgoats]

I opened this tab when it was at 00:57 ... LOL TO YOU TOO

Excellent video by the way.

[brutishquito]

Ever considered starting your own school sal? I would certainly promote it! And I would go there if i were not 19! haha

[mjmidhunmj]

superb!!!!

[Alldevouringsnail]

is this yr 12 maths or university (college) maths

[soulreaperichig0]

@Alldevouringsnail year 12

[oliviaoneill]

@Alldevouringsnail university maths :)

[13Lazio]

thanks bub



[Immortalkosta22]

Thank you very much, you really helped me :)

[Agamemnon1002]

I am an engineer specialising in Finite Element Analysis in solving structural analysis problems in industry. This involves the solution of large systems of linear equations of the type [A][x]=[n]. I teach FEA analysis and I always strive to improve my methods. Well, this gentlemen is very good. His style of teaching is friendly and considerate and is obviously a man who enjoys his profession. I would like to buy him a drink. Good luck to all of you students for the future.

[dannyguy1000]

Thanks man, u are even better than my math teacher :)

[ashnabwa7d]

can i divide the whole row so i can get 1?

[guithorlox]

Why would they even teach the other meadod? this is so easy!

Thankyou vm! :)

[grillz290]

Thank you so much Sal, you saved my ass for tomorrow's exam, so easy to understand.

[oddvidios]

9:40

mind = blown

[MrKamran425]

you should get paid by youtube (not us) :P

[littlemisscuddlesxx]

hi im wondering what i should do with this system

reduce to row echelon form

x1 + x2 + x3 = a

2x1 − x2 + 7x3 = b

−x1 + 2x2 − 6x3 = c

What conditions must {a, b, c} satisfy in order for the system of equations to

be consistent? If the system is consistent, will the system have none, one or an

infinite number of solutions? Determine a solution, if a solution exists, in the

case where {a = 3, b = 1, c = 2}.

[TheFutureIsRightHere]

The longer method is actually easier (at least for me). Thank you!

[DannyLimTV]

i think you should do more complicated numbers next time... :D

[StaticShock1100]

BEST. CRAMMING-THE-NIGHT-BEFORE-A-TE­ST. VIDEO. EVER.

[JonathanLindroos]

I finally get it :D

[paskavatta]

Nice videos. I think intuitively best way to study inversing matrices is resolve x since it is known that Ax = I. No matter what size matrice A is we can always multiply it by x which every elements needs to be solved then. Of course gauss jordan does pretty much same elimination by row but solving at least couple of times x it could help to understand idea behind matrice equations.

[Crisp3333]

thank u very much khan

[Helllocutiepie]

This method is way less confusing then the other one if you ask me... WAY LESS, indeed!

[Helllocutiepie]

Haha, this mehtod is so good, it makes me sad that I even watched the other video!! When I just need to know one for my exam and all. I would like to know the "formula" behind it, why this works, if you may, but no time now!!

[ace2a66d20]

Do you have to rewrite the entire matrix every time? or could you just add new lines and work with those?

[CogitoErgoCogitoSum]

Algebra 2? What does matrix algebra have to do with the algebra one learns in middle school? I am a multivariate calculus student at the university level, and American academia has never once exposed me to a matrix.

[BullShitThat]

@CogitoErgoCogitoSum What he is teaching us right now, is commonly referred to as linear algebra 1 in universities. When he says "Algebra 2" he really means linear algebra 2, the following class after learning linear algebra 1. There is also Algebra 1 and Algebra 2 classes at the university level which comes after multi-variable calculus and vector calculus.

[budman533]

lol @ 0:54

[skulsaw]

you don't even know how helpful you are.... for my further maths a-level :) thank you so much :D

[LAnonHubbard]

A nice alternative way to find the inverse. Will this work on larger square matrices? Like the intuition bit at the end. Made sense.

[XpresloX]

what is serve those number ?

thx

[LeahWitchiga]

Excellent! Thank you a lot!

[iversonjack]

thanks for refreshing my mind!

[cooney147]

Thank you! I'm at uni but have never done matrices before and have to learn everything i can. 2 hours watching your very clear videos and i'm well on the way! Hero.

[Iamatheist1234]

thanks! Sal! you didn't confuse me at all now i know how to find an inverse of an matrix in a faster and more efficient way AND I know it's intuition.'

Thanks! you have been very helpful!

I saved my life for the quiz tomorrow!

[Aviation2291]

Sal you are amazing!!!

[ChippZanuff93]

dude, you should get an award or something... you are awesome!!! you surely changed the world, seriously!

[Michalbasavraham]

@ChippZanuff93 He has gotten them. Go to his website and there's all kinds of interviews and features.

[ABCba5tard]

Saint of Math!~!!~~~!!!~~~!!!~~~

[ronijun888]

Hi, I just want to thank you for teaching that Gauss Jordan. I have this Instructor and he taught the Gauss Jordan. I have my Sci. Calculator, I solved an Inverse Matrix using calcu then my instructor solved it by himself. I wondered why the answer of my instructor and the answer on my calcu were not the same. And finally, I found it here. My instructor was wrong. I told him the right solution then. Thanks for help. -Aeon, Philippines.

[frother]

From what I remember of linear algebra, it's row echelon form around 2:50, not reduced row echelon form. For it to be reduced, all nonzero values have to be on the right diagonal

[SInnerMario]

Your are really good man , ur stepin down to the lowst level possible so that any student with no further knoledge can understand this , and this is actually the best thing a teacher can do .

very great job , i salute you for that :D

[virginialikesyou]

thank god this method exists!! i hate the other method

!!!!

[RichyBabess]

Thanks!

When you first started the video, you said that it was more fun, and i lol'd a little, but i can actually see this being a way of doing it that isn't really tedious, just following steps. I quite like just fiddling around with something until you get the right answer, so thank you :)

[Sinead445465]

holy.....!!!!!!!!!!!!!!1

[beatlesb50]

You are amazing! I'm in calc 2 in college and you save me every time!

[06forzajuve]

Thank you. Question though. Where would i use this in the workplace?

other than being a teacher and teaching it

[MultiRayKing]

@06forzajuve look it up economics, biometrics, statistics, cryptography, etc...

[prodvig]

русские

[aduitdfeklfhl]

couldn't understand how that was inverse of A (the 5th sum)???

[MiniGeek31337]

Why does everything look so easy with you?

Thank you again!

[kami645464]

Thanks for the great easy to learn free education on YouTube.

[Tekhsheen]

Saved about 500$

[DrKaito10]

Where do you prove the stuff about elimination matrices?

[patilnikh]

Dude, are we playing with this?

LOL

[prodvig]

рор

[xOlixObscenex]

i learned this way in school. its too difficult for me, honestly. the first way was much easier for me for some reason.

[ravenslayer2000]

probably because there are clear steps on what to do first

With this method you have to try to find out what will work best

[yynotx]

no cramer's rule inverse matrix? sob :{

[prettynathie]

THE INVERSE THIS TIME HAS ONE SMALL DIFFERENCE WITH THE FIRST... the element a(3,2)-row 3 column 2- last time was negative...this time its positive! which one has the mistake in it??

[amjPeace]

Hi prettynathie. I think you're looking at the Adj(A) matrix in the previous video, not the final inverse matrix, which was correct and identical to this result. Maybe you forgot to multiply all your elements by the inverse of the determinant, which was -1.

Have a Happy New Year.

[Milchi7]

Both are exactly the same. just all the +/- changed. So, no mistake

[sairdair2]

it's too much easier than the 1st way in part 2

[lyaskoff]

awesome! much, much better than the other way of solving this :) thanks Sal!

[killerfriend94]

not bad

[TopperHarl]

I dont want to get in to details, but you are not allowed to subtract rows in linear algebra. What is being done is addition of the negativ row.

You can add rows, interchange or multiply with a non-zero constant.

[alankarmisra]

Technically that holds for regular algebra too i.e. subtraction can be construed as addition of a negative. I guess "subtraction" is just a convenient way of saying "adding a negative", so its cool if he says "subtracting one row from the other".

[baseball111490]

excellent job. great tutorial and very helpful. definitely easier than the other method.

[Vonzi0000]

{8/123, 7/123, 10/123},

{11/123, 25/123, -(17/123)},

{4/123, -(58/123), 5/123}

I got that using a programm, sems to be way to hard to do it the normal way.

[tumbleweed90]

Thank you, this helped a lot. Can you do on on simplex method and duality?

[oib4696]

lkrippler, sometimes I find it easier to use the method described in part 2 over Guass-Jordan elimination. But either way, it's much faster to just check with a calculator.

[mgtuta]

So helpful, i never took Linear Alg.... but i need stuff from L.A to do some diff. equation.

It's really man.

Thank you so much

[chrisness1472]

Thanks, this was a great tutorial.

[Endureil]

What can I say, LOVELY! I'm trying to learn graphics programming and matrices is a must for calculating the transformation, rotation and scaling for 3D objects through a 4x4 matrices, i'm hopting to learn alot from these movies of yours as I didn't take any high end math classes in my high school :)

I'm an artist that's interested in graphics programming :)

Thanks again :)

[manolon1000]

Thank you

[Tajarnia]

Wow, they didn't show us this in class. Pretty awesome, thanks!

[DeKamii]

your videos are extremely helpful. thanks for the upload.

[Painfoot]

Wow... reminds me of how to solve a Rubix cube

[masterconcept]

thank you very much

[pinkunath]

thanx

expecting more lectures from u

[killersdeat0]

Thanks! very nicely done.

[Lolzerd]

good job salman khan :D

[Ml11lON]

This is great great help!

[bruno06arg]

He's better than my algebra teacher!

[bevherly]

Excellent teacher.

Thanks for the help

[bevherly]

Very well taught. Thanks for the help.

[FarFromEquilibrium]

oh these are soo much fun :D

[B1991M]

thanx

keep t up

[cuteprincess148]

Hiya!

I really enjoyed watching the video and it really helped me!

Amazing, keep up the good work!