Inverse Matrix (part 1)

[444zane3]

u are a boss

[sk95star]

HEY! its 2012 ;) <3

[sk95star]

After school = youtube

[SuperToaster1234]

this should be how they teach math "Ok class, today we're learning about Vectors. Now go home and search up Khanacademy on YouTube" My work here is done.

[12ig0]

Thank you, sir. Very helpful, straight forward refresher.

[neverletanybody]

Thank you Khan, you're the best, keep helping people me.

[deltasuperprime]

AND THERE YOU HAVE IT!



[txdx]

whaaaaaaaaaaat have I gon to? is any of this to do with the film ??help

[txdx]

@txdx ok im on the khanacademy channel lol my bad

[EricGrigor]

did he write in green, on a black background to make it more like the movie?? =3

[01kAzE10]

perfect !

[makoosik]

thanky you, something that's confused me for years is now crystal clear. wish you were my algebra II teacher, i would've learned something

[emilsonlimbaga]

hey prof. what is your lastname.

[jackkatez]

@emilsonlimbaga his name is salman khan

[emilsonlimbaga]

your great ,please don't stop doing like this.its called blessing to those who are slow in math.

[thegreen895]

this guys tells it good but puts so much bullshit in it making it too long

[anewmach1ne]

Thanks, Khan. You are the best teacher I've ever had.

[Rambunctiousholics]

thank yew sooooooo much!!!!!!!!!!!!!!!!!!

i dnt even have to go to school anymore xD

[emilsonlimbaga]

God will give so much blessings in life because you share your knowledge in the whole world about what is determinants & inverse.yyyyyyyyyyyyyyyyyyyyyy­yyyyyyyyou are very excellent creature of God. Thank you.

[jameswell92]

You are good ! Please continue ;D

[acevedohiram]

Thank you now it makes sense

[soulreaperichig0]

This video is most popular with:

Gender Age

Male 25-34

Male  45-54

Male 35-44

This proves teachers learn from khan's video xD

[Killuminatismd]

@soulreaperichig0 haha excellent analysis!

[Karensuckssobadly]

I can actually follow through. I'm in 8th grade

[199sina]

You are awesome dude,Piss on my teacher...

[elapplzsl]

dude u r totaly good at this & thanks for the video

[MrSurfsAlot]

13:38 your happy because you didn't make a simple mistake and wouldent have to film it again <3 l0ve YOU

[directsll455]

I didn't know he used MSPaint to do this...this guy is AMAZING! I love his teaching...he makes everything so clear that someone could learn this entire subject just from his videos. Great job man! :D

[DrTupac1]

Thank you so much ..

[MrRakso11]

thumbs up if you didn´t pay attention i class

[mufc4everch]

@MrRakso11 :( I wish dearly that I did. These should be supplementary

[MalikFromAlgeria]

@MrRakso11 thumbs up if you didn't even go to class

[TheLoveformankind]

I LOVE U KHAN !!!!

[wesrdavis]

Thank you so much! You have helped me in Biology, Physics, and now Algebra

[Mikko2143658709]

That there looks some complimacated algaebra.

[Immortalkosta22]

Thumbs up if you think we can learn linear algebra from this man instead of f***ing books!

[guerillachan20]

I enjoy learning from you.

[Estefania521]

AH! Totally makes sense now! Thanks!!

12 dislikes? jealous teachers i suspect.....

[fallofsaigon]

THANK YOU!!! FINALLY EXPLAINED BY A HUMAN BEING!!! IT FINALLY MAKES SENSE!!! :)

[SuperMegaJew]

This guy is really good, I just wish his handwriting was a bit better. Thumbs up if you think he should practice his handwriting.

[SWATsqad]

thank you!!!

[rayray66]

so good, you should add these videos to pornhub or xvideos so theres more places for people to learn

[OfficialHuMan]

"but this is good exercise for multiple parts of the brain"

that line might change my life...i just realized my problem...i had always been the math genius when i was young so i became over confident....i used to find maths so easy that i never had to even try to understand something...as maths became complicated i found it becoming harder..this is because i usually did not try to spend time on a question if i dont understand it because i wasnt used to it...I DID NOT EXERCISE MY BRAIN!!

[desisk8r11]

anyone notice ad - bc.... thinking about time.....6:41

[GooyahsRS]

Around 7:22, you say to make the top right and bottom left "negative" when i think a better way to say this is to switch their sign (+ to minus, minus to plus) sorry if you did say that further on, but just a nice clarification. Thanks for the amazing videos! I learn more here than at all my private classes, much less school.

[chicogotgreen]

Oh my lord. And I just realized.... unlike my professors, I can pause you awesome instruction when I need to text! Ok, you are officially my hero.

[chicogotgreen]

No joke... You are the only lecturer that I pay attention to. I dont even go to my math lecture anymore. And I'm in a top 5 engineering school. You rock my face off. Its that extreme, I had to go oldschool.

[AlligatorJack01]

@chicogotgreen remember that this is just absolute basic beginner's stuff in math.

[Rankpenguin]

What is the application he's using? Seems pretty cool.

[iamundergrace]

@Rankpenguin ms paint

[Rankpenguin]

@iamundergrace No, it's not. I figured out that he's using a tablet, and the application is called SmoothDraw3.

[Millearl]

thumbs up if you thought it was the movie

[itechkid]

@Millearl not.funny.

[Shakespeare1612]

So an identity matrix, in matrix multiplication is like the number one in regular multiplication, but can you come up with more useful forms? That is can you have can we use like a matrix B over matrix B to simplify a rational matrix?

[forgefwa]

I have never heard of this Matrix Multiplication!

[tehmadcap]

Too much green in the matrix? Never!

[CosmicKitten89]

11 people are math teachers.

[NewgroundsOwnSBB]

so.. is the green+black colour you used for the first 4 minutes an intentional reference?

[1999vandal]

Khan singlehandedly clowns the entire U.S. education system

[jbnshah]

this isn't some guy...this is our Sal

[moyaish]

im starting to think this guy is from the matrix

[mariodippenaar]

This guy is so good, he can see the matrix. And probably fly and stop bullets.

[BeatySword]

@mariodippenaar Shall we call him Neo?

[humayunism]

gr88888888888888



[humayunism]

Awsome video exellent vow....

[MilitantNinjaLo]

I leanred more in 14 minutes and 14 seconds on this vedio then I have in days in my Algerbra class... thanks for the upload, Excilent vedio 10/10

[tIs4gatorbait]

You're just driving along, everything is fine and then at 6:36 an 800 pound gorilla throws your car off a cliff.

[shoaib36027]

thank u so much for such a helpful video

[AbsoluteMathematics]

I'd hate to question you because you've made quite a few videos and you seem to know what you're doing but I believe your cofactor should actually be

|d -c|

|-b a|

I'm talking about at 7:40 ish

[pjtechy]

love ur vidz ... god bless u..

[7kn8]

these videos are really helpful, my teacher couldnt explain this like this guy!!!!!!!

thanks for the upload

[capitandelfuego]

is the

|d -b|

|-c a|

the transpose of matrix A?

[Moviefreak247]

@capitandelfuego no the transpose is the rows and columns switched.

So if A = |a b| |c d|

The transpose of A would equal

|a c|

|b d|

[tubester358]

This was really good, it was a refreshing way to revise (or get re-educated in my case), thanks a lot.

By the way, what program do you use, it looks fun to work on?

[Ratedownunder]

10 people are colour blind

[hniang2]

haha! so fuuny... even the brilliant got confused after solving tons of math questions lolss... now i don't blame maself for getting small errors in ma tests lolss

[Doouzey]

10 people are agent smith clones

[Doouzey]

10 people are agents

[zeffii]

i think i get it now :)

[hichambenqlilou]

hahahahah even more fun.. lool suuree... but thanks tho

[sahme7]

A little bit confusing at first, but understandable.

[Mike01010011]

Thank you so much!

[ChRIs23696]

my maths teacher said this today and asked what a matrix was

i said its a movie containing someone named neo who finds out that he is merely in a fake world named the matrix and the world isactually an awful place run by giant floating squids

didnt go down too well...

[hniang2]

@ChRIs23696 lolsss you answered really well... if i were your teacher i would give you straight A lols

[IXIELCHINGONIXI]

i fucking love you

[JefferyHere100]

Thank you

[Wuphlez]

Great explanations! It's very nice to have a source to go to for a refresher as apposed to flipping though complicated definitions in textbooks!

[Bowen96dude]

This guy + youtube can have all the math teachers out of jobs in a fortnight.

[david52875]

@Bowen96dude Except that the teachers' jobs are subsidized by the government, so even if you can learn infinitely better by watching Sal, you still have to spend 7 hours a day at school.

[WootMapler]

i love you

[flowersofmoe]

i love your deep voice.. its soothing while im learning haha (im not a creep) :)

[xlaym]

by the way, theres an even easier way to figure out the inverse of a matrix (and whether its possible or NOT). write the matrix A next to the identity matix I. now try to form A to I and make the same operations you do to A to I aswell. if this is possible, I becomes your a^(-1) matrix.

remember: if det(A) = 0 you can NOT invert it!

message me over youtube if you got questions.

(i hope this helps, im not a native speaker^^)

[Jape1990]

What if d=0?

[xlaym]

nothing spezial will happen, you can put in anything you like, 0, 23.5354, pi, phi, e, 50x³, z (complex numbers), anything, thats what this whole thing is about xD

[THE16THPHANTOM]

for a moment during this video i thought about matrix the movie.was it a coincidence that you used the green color?

[CogitoErgoCogitoSum]

Did we assume the associative law when conceiving of an identity matrix in the first place? Or did we first assume directionality, determined the identity matrix, and then after the fact that proved associativity?

I guess what I mean to ask is, "how do we know there arent directionally-dependent identity matrices?"

[moreeso]

i have a exam today , and that was really really helpful

thanx , wish me luck

[Legatus777Legionis]

where the hell is neo???? :))

[sayitisntsokthnxbai]

Praise the lord, I understand!

[dchak67]

patrckMJT is a much better teacher!!!

[amiego11]

where would i be without ur explaination!!best maths teacher i have ever come across to..

[fanSmath]

on this page matrixcalc.appspot.com/inverse­.html can one calc inverse matrix

[pooskie91]

I wish there was some way of liking all the Khan videos

[toiletscrubbr]

how do you take the invers of a 3x3

[Yankeesroxs]

Thank you so much!!

[mrpieluvr]

OMG THANK YOU SO EFFIN MUCH, I HAVE EXAMS TOMMOROW AND MY TEACHER SUCKS AND YOU JUST MADE THIS SO SO SO SO SO SO SO SO MUCH SIMPLER

[sinareth]

thanks for upload. i have a final tonight, and i'm study for it all day, now i got ans for one click.. you are so helpful.

thanks again

[LAnonHubbard]

The matrix you come up with at 7:00 which has terms d, -b, -c, a in it... What's that matrix called?

[LAnonHubbard]

@LAnonHubbard In a later video he identifies it as the adjoint.

[LAnonHubbard]

I like this. I got a bit confused with the book after a while. The book plus your videos is illuminating.

[desmosedicigustav]

HAHA, exactly, God bless you!

[abcarin0O0]

excellent,thank u

[GlorifiedTruth]

Very informative and clearly explained.

[dennismoore56]

thank you for these matrix videos they are like having my math teacher at home without his moving to fast and being a creepy tall italian old dude.

[Kaish3k]

Someone is typing in the background, I have ADD. Can you tell?

[FILLIIAN]

Good tutorial dude!

[nameless527]

iv failed many classes cuz u dont understand this (math), but im subing and gonna study ur videos, thx man

[dadoftwins031404]

This vid helped me 100%. I understand inverse matrices after a 14 minute video. sweet!

[d987b]

I spent all the night trying to understand the Gauss-Jordan method, but this seems to be more straightforward. Thanks a lot, this has been very helpful!

[reelgoodfishing]

this is seriously awesome. I really wish I could just get a degree from Khan Academy than UCF. way easier to learn the same stuff here than the way they teach there

[swu880]

10 of 10 stars :) 

[hahaeliz]

thank GOD there are people like you who post videos on youtube who are linear algebra retarded

[daguerras1]

no mames wey te entendi mejor ati en ingles que a mi profe en español gracias muchos tank´s

[villy8778]

Great video...

but : -15+9= -7 ??????

[quimy9]

YOU'RE MY HERO BABYY!!!!!!!!

[quimy9]

YOU'RE MY HERO BABYY!!!!!!!!

[ayanxoxo]

i love you xD

[volopok]

wow i did not want to go to a math video

[tungkeat89]

5 by 5 better let the computer hahahaha

[ABCba5tard]

thx for helping me it will help me understand algebra 2 much better

[MyFightQuest]

whats funny is that i came to this video from an add that was on the side of a video from the matrix movie -.-

[faithie70]

Some matrixes have a order of 1 followed by trillions of zeros

[indokidzz]

thx for the vids man, im learning this concept for mathematics C next year

[MrGtrCalculus]

During 4:23 to 4:29 you made a mistake (not purposely). It is important to mention that the value "a" cannot be zero since its inverse " 1 / a " must be a number. Remeber, we can't divide by zero. Also, somewhere else in the video, (at about 7:03), you did not mention the case when ad = bc (i.e. when the determinant is zero ). Determinants only make sense when the matrix is a nonsingular n X n matrix. Other than that, you did really good. It's nice to see some Linear Algebra. =)

[doogiski]

@MrGtrCalculus Your nitpicking makes me sad. I think we all realize what details were omitted in this INTRODUCTORY video...

Anyway, good video, thanks for the refresher!

[emilyxx93]

i have an exam in this today... i think after watching this i might actually pass :P

Thank you so much

[songxialin]

it save my life god

[Xsuprio]

... I guess I wouldn't be on the list of people who get to go on he spaceship to save humanity.

[CurlyVogel]

I was genuinely amazed at the end of the video! :O Math is awesome! you're the man! *bows*

[brashboy0403]

this video was ridiculously simple

not only r u an amazing virtual teacher but you just made sense of my double further maths class today

Thank you =

[shadowkitty1988]

My Professor made it seem much more complicated than it actually was. I was having so much trouble figuring this out--searching my textbook and my notes--until I saw your video. Your explanations were so easy to follow, and it helped me realize just how simple finding the inverse is.

Thank you very much!! Now I'll have no problem on my upcoming exam. :)

[fuckfatchix]

very good video of an 2x2 inverse matrix.

Thank You lots, BIGG HELP!!!

[RAJISHNA98765]

HeY mE JsT HaTe mtHz.......sOooOo CoNfUsInG....uGh....I AlWayZ wOndER Y SmE PpL CaN dO eASiLy....???

[123MrBee]

Back it up to a level where you get everything.... then start from there.

[drpepper5001]

this video makes me feel not smart

[onlyAerik]

Why is it that this comes back easier when you're doing it then when I learned matrices in 10th grade... oh wait, nvm, that answered itself.

[ideabook]

thank you man that really helped. the examples that are shown in the mathematic book never explained how to do this steps exactly . but you explained very well and very easy. thanks :- )

[yamahabibi]

Excellent explanations

Great video and thanks for upload.

Pls make more maths video; its really a lot of students.

10 out 10.

God bless you.

[dianaferreiro]

Thank you so much !! Greetings from Madrid :D

[mordagau22]

hi, i am german and i have to say : very good. i liked it

[ThePeacefulResistor]

3x3 is even more fun lmao

[AintYouThaSameCat]

thank god, you have saved me brotha. i didn't quite get it at my class so when I wanted to study on it at home, i realized i didn't know how to do it, and the text book is just rubbish you can't understand anything! but anyway cheers for you mate! makes matrices puny haha.

[theMou]

1000*thanks :)

[danieljapan]

My man, on behalf of all the IB students in Iceland, I would like to thank you personally.

[timetrialtom]

Thank you.

[TheeRussian69]

-15+9= -6 not -7

[mrmandude1121]

it was -15+8, you just couldn't see it very well

[TheeRussian69]

lol better than my teacher and it took half of the time

[vanitakurse]

All your math videos are great. You make math look simple and easy. Thanks for posting these videos.

[sodr2]

this saved me

i would like to emphasize "saved" but alas, i cannot express it through mere characters

[veanutella]

awesome! greets from germany ;)

[atrickpay11]

And the government told me that muslims were terrorists....phttt...thx Sal!

[middlj14]

nice one lerrrd!

[imagoninjaonu]

TY it helps a lot!