Dimension of the null space or nullity | Vectors and spaces | Linear Algebra | Khan Academy

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Dimension of the Null Space or Nullity
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Пікірлер: 68
@Peachereis
@Peachereis 11 жыл бұрын
skipped whole 6 month classes watch all videos . passed
@DannyzReviews
@DannyzReviews 10 жыл бұрын
This guys is the best. But let's face it if universities and colleges could hire professors like this guy who can "teach" a concept and "explain" thoroughly then people would not even have to resort to watching his videos as last minute life savers before a test or exam. Just because someone has a PHD in a subject does not necessarily mean they can teach it. They might be a complete expert and genius in that subject but getting other people to learn it and teaching it to them is a completely different story. The institutes should look at Khan's videos as an example how a great teacher should explain concepts and questions to someone rather than looking at whether they have got a PHD or doctorate in a course.
@rwarzor
@rwarzor 9 жыл бұрын
A lot of those teachers with PhDs are being paid by the college to do research, teaching is their secondary profession. Research brings in big money in grants and publicity to the universities, so they hire smart people who can conduct research
@DannyzReviews
@DannyzReviews 7 жыл бұрын
Haha, didn't think I'd be returning to a 3 year old comment. To be honest, I am also to blame for my lack of incompetence. I procrastinated and would even skip some classes which led to me being in a state where I would have to watch these last minute videos online. I still stand by what I said back then though. treasy​ brought up a good point a lot of profs are actually at institutions for research as their primary job. I had one prof who's lectures were pretty meaningless, but he had contributed a truck load to the university's research. I wrote that comment because I was just really frustrated and was just venting when I should have been studying LOL
@JTX8000
@JTX8000 7 жыл бұрын
11:40 for Dimension of Null space, you're welcome
@ThinkPositive00
@ThinkPositive00 10 жыл бұрын
Why can't every lecturer explain as clearly and simply as this?
@Yadinma
@Yadinma 10 жыл бұрын
don't u think thats like asking, why cant every basketball player shoot free throws.....
@SomethingSoOriginal
@SomethingSoOriginal 12 жыл бұрын
Not just vaguely useful, EXTREMELY useful.
@901help2
@901help2 8 жыл бұрын
Vaguely useful? are you kidding me, thus was great! Thanks for the help Sal!
@industrialdonut7681
@industrialdonut7681 5 жыл бұрын
Jesus christ that ending "Anyway hope you found that, vaguely useful" LOL
@GodsOfMW2
@GodsOfMW2 6 жыл бұрын
Love you Sal. Your videos make me look like some sort of super genius in class!
@Waranle
@Waranle 15 жыл бұрын
You make it so clear. Thank you
@vikasutube100
@vikasutube100 7 жыл бұрын
God bless you! The tutorial was amazing!
@junkeychan
@junkeychan 12 жыл бұрын
I come listen to this guys voice and all my stress about up coming exam goes away.
@musabahmed3341
@musabahmed3341 2 жыл бұрын
Khan for president!!!! 2022
@basmaal-ghali9174
@basmaal-ghali9174 8 жыл бұрын
Useful... thank you..
@Jef11235
@Jef11235 13 жыл бұрын
Thanks so much, this is EXACTLY what i needed! :D
@bhuwandwivedi513
@bhuwandwivedi513 8 жыл бұрын
thanks it helps a lot
@UltramanII
@UltramanII 13 жыл бұрын
Thanks guy you just saved me from my mid-term!
@uolwass
@uolwass 13 жыл бұрын
absolutely amazing!!! u are a genius, thanks sooooo much
@KingRobbStark
@KingRobbStark 15 жыл бұрын
Dude, awesome.
@spsorn5433
@spsorn5433 Жыл бұрын
Thank you so much. I love your explanation.
@katlegomalesa5907
@katlegomalesa5907 9 жыл бұрын
perfect!!!
@faisaltg14
@faisaltg14 8 жыл бұрын
thank you very much sir , i have final exam in this after one hour you really explained everything for me better than that one we called prof in our college
@yousef.al-assaf
@yousef.al-assaf 7 жыл бұрын
faisal alfaisal كيف كان الامتحان 😂
@johndafish7829
@johndafish7829 10 жыл бұрын
Thank you so much man!!!! You are awesome!
@mastercgmr
@mastercgmr 13 жыл бұрын
Thank you sr!
@jstdun
@jstdun 11 жыл бұрын
Damn this was really helpful.
@zhijieli12
@zhijieli12 Жыл бұрын
verrryyyy verryy useful !!!!!!
@A-003
@A-003 14 жыл бұрын
A thank you would not be enough . . . I dont know wat to say God Bless You
@twmzzang
@twmzzang 11 жыл бұрын
so good
@tuyetlan888
@tuyetlan888 13 жыл бұрын
Hi there, I would like to know if I did exactly like you did in the video, except I put in row echelon form instead of a row reduced echelon form. Would I still be able to get the right answer?
@pojorobo1
@pojorobo1 11 жыл бұрын
i have a test in 20 minutes and his videos saved my life
@wadiczka
@wadiczka 12 жыл бұрын
Amazing job, trying to get ready for linear algebra exam tomorrow.
@antonioalonso5831
@antonioalonso5831 4 жыл бұрын
wadiczka How’d it go? Lol
@lemyul
@lemyul 3 жыл бұрын
ty
@HariHaran-sl1pg
@HariHaran-sl1pg Жыл бұрын
God Bless..
@Car1ll
@Car1ll 13 жыл бұрын
Doesn't this mean that the dimension of A is equal to the number of collumns minus the number of rows of A. Since the reduced row echelon form will allways contain a number of pivots equal to the number of rows?
@sachinduhan3022
@sachinduhan3022 5 жыл бұрын
i wish i can hug uh for ur help
@justinv3
@justinv3 15 жыл бұрын
yup
@Robin-pc3jf
@Robin-pc3jf 5 жыл бұрын
Excellent video, though why does the calculation for nullspace start with B but end with A?
@genericusername337
@genericusername337 9 жыл бұрын
your handwriting is just like mine!
@yanyancui1601
@yanyancui1601 7 жыл бұрын
what if the free variable is not linearly independent?
@KiDFRANKKK
@KiDFRANKKK 12 жыл бұрын
Sick
@TheGreatSpanski
@TheGreatSpanski 11 жыл бұрын
Jeeeez what snoozzzzeefest. #YAAAAWWWWWNNNN
@sanmvegs1641
@sanmvegs1641 6 жыл бұрын
Let me ask you a question... is number of non pivot columns the nullity of a matrix and number of pivot columns is the rank of the matrix?
@realvideosrv1879
@realvideosrv1879 3 жыл бұрын
I cant find this complete playlist? Please link anyone? :,(
@comtrang
@comtrang 11 жыл бұрын
When the pen hovers closely above the tablet, the mouse is responsive. You don't have to be in contact with it. I use one for Photoshop and that's how mine works.
@codex8538
@codex8538 3 жыл бұрын
are the vectors associated with each free variable linearly independent always?
@oneinabillion654
@oneinabillion654 3 жыл бұрын
Yes because only that vector associated with the free variable has a 1 in it, whereas it is 0 in the other vectors. So these vectors are always linearly independent after rref since theres no linear combination to represent that "1"
@WouterNed
@WouterNed 11 жыл бұрын
Then how does he move the pointer around without writing?
@vabs9211
@vabs9211 14 жыл бұрын
thx mate..u saved me from failing maths.....lolz
@whitesanity4965
@whitesanity4965 4 жыл бұрын
luv ya m8
@applecider98
@applecider98 11 жыл бұрын
Teach at my school please???
@darlenemontesano3214
@darlenemontesano3214 6 жыл бұрын
how are x2, x4, x5 free variables?
@GodsOfMW2
@GodsOfMW2 6 жыл бұрын
If you look at the columns of the rref matrix, they do not contains any pivot ones. So if you were to expand the rref matrix, the free variables are the ones that appear in both equations.
@howtoguro
@howtoguro 6 жыл бұрын
It actually doesn't need to be in RREF btw. REF will work better since it's a time saver. Row eschelon form is good enough because the numbers will change but the pivots will not. Since the rank-nullity theorem is dealing strictly with the # of pivots col and # of non-pivots col
@srockerrr
@srockerrr 5 жыл бұрын
God I love you.
@leon-lm7uf
@leon-lm7uf 3 жыл бұрын
why is my linear algebra class not using matrices--
@nickchi8723
@nickchi8723 2 жыл бұрын
basically the number of free varible in the matrix is the dimension of the null space. Dude why must linear algebra has so many terms. nullity = dimension of null space = numberof free verible in rref. Spend 10 min just want to know this and is at the last part of this video....
@comtrang
@comtrang 12 жыл бұрын
I'm pretty sure he uses a USB tablet to do these
@bensher2291
@bensher2291 7 жыл бұрын
I wanna kiss you right on the fuckin mouth Mr. Khan Academy
@user-lb1fl7sh8m
@user-lb1fl7sh8m 7 жыл бұрын
beast mode!!
@6124279
@6124279 11 жыл бұрын
Hes so smart, not even funny
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