9. Independence, Basis, and Dimension

MIT 18.06 Linear Algebra, Spring 2005
Instructor: Gilbert Strang
View the complete course: ocw.mit.edu/18-06S05
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9. Independence, Basis, and Dimension
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Пікірлер: 308

  • @he.smile_
    @he.smile_6 жыл бұрын

    ma boi gilbert saving my butt once again

  • @stv3qbhxjnmmqbw835

    @stv3qbhxjnmmqbw835

    3 жыл бұрын

    How is you butt now? Is it safe? I hope it is...

  • @aarifhussain3700
    @aarifhussain37004 жыл бұрын

    Just blessing for students who couldn't go in mit

  • @anticlause
    @anticlause6 жыл бұрын

    I feel so lucky to be able to pause, rewind, and re-watch. I might have struggled trying to take notes while letting the incredible insights sink in. Are we getting a better education online than even the students in this very course?!

  • @tanmaysinha987

    @tanmaysinha987

    5 жыл бұрын

    yes definitely, I have problems in live lectures. I understand much better in video lectures

  • @iahmeed_1

    @iahmeed_1

    4 жыл бұрын

    agree

  • @muditsinghal.1493

    @muditsinghal.1493

    3 жыл бұрын

    2020 read this comment

  • @avdhutchavan3044

    @avdhutchavan3044

    3 жыл бұрын

    No, they were provided the videotapes for these lectures.

  • @eneskelek1405

    @eneskelek1405

    3 жыл бұрын

    maybe you are right about one side but you cannot ask to teacher whenever you want .

  • @elyepes19
    @elyepes193 жыл бұрын

    I dub this lecture as "Everything your parents didn't tell you about Linear Independence and you were afraid to ask" Thanks Professor Strang, you are a wonderful human being

  • @ahmadabdullah262

    @ahmadabdullah262

    2 жыл бұрын

    😂😂😂

  • @ElmerOmero14

    @ElmerOmero14

    7 ай бұрын

    You had mathematicians as parents?

  • @GavinoFelix
    @GavinoFelix10 жыл бұрын

    @ 7:40 - "Let me take an example where I have a vector and twice that vector...If the word dependent means anything, these should be dependent"

  • @muhammadqail5280

    @muhammadqail5280

    4 жыл бұрын

    Gavino Felix ko

  • @salinamu
    @salinamu Жыл бұрын

    You are doing so many people a favor by posting this. Seriously.

  • @Peter_1986
    @Peter_19869 жыл бұрын

    @joaopp3 Yes, some lecturers become so used to their courses that they start to forget what it is that is considered difficult by new students, and stupidly assume that "everyone" "just knows" what all math symbols and proofs mean. In my opinion, the best way to teach a new concept is to give a quick summary of what it is going to be about and then give a lot of examples, and encourage the students to help solving them. That's exactly what professor Strang always does, and that's one of the reasons why he is so amazing. I also think that it is very important that a lecturer shows a genuine fascination for the subject, and is always willing to help the students and respects that some of them may have a harder time than others with certain parts; and it is also a huge plus if the lecturer has a sense of humour and presents the lecturers in a relaxed way. And Strang seems to have all of these qualities as well.

  • @naterojas9272

    @naterojas9272

    4 жыл бұрын

    At first I thought you were a hater....

  • @adamghafouri8755
    @adamghafouri87552 жыл бұрын

    29:35 The vectors are not independent. 2*[2,2,5]-[1,1,2] = [3,3,8].

  • @ALittleLifeWithDriedTubers

    @ALittleLifeWithDriedTubers

    Жыл бұрын

    Yes this was really making me second-guess myself. Thanks!

  • @guptaachin
    @guptaachin6 жыл бұрын

    I could not help smiling when he just so smoothly introduced the concept of Basis Vectors. I was never able to understand it and now it seems that it was always so easy. The pauses he takes during explanations really builds you up and makes you think. Do not fast forward. If he is speaking slow. There is a reason. I am sure he is experienced enough to technically garble all the information and leave. But he does not. Please respect that and you will actually start learning.

  • @joebrinson5040

    @joebrinson5040

    5 жыл бұрын

    Exactly

  • @kub1031

    @kub1031

    3 жыл бұрын

    all what I am thinking is like if he is an instructor, who is mine?

  • @explore_vj
    @explore_vj4 жыл бұрын

    Completed 8 videos, watching 9th, 26 more to go!

  • @arteks2001
    @arteks20013 жыл бұрын

    There are nonzero solutions to Ax = 0 if m Definition of linear independence of vectors 4:36 Examples of linear independence and dependence of vectors 7:05 Linear independence of columns of a matrix 13:18 Vectors that span a (vector) space 18:05 Definition of basis of a vector space 21:26 Examples of basis of vector spaces 24:12 (Error referenced in next lecture 27:43) Definition of dimension of a vector space 33:17 Examples of dimension of a vector space 37:44

  • @roostaj
    @roostaj14 жыл бұрын

    His teaching style seems casual and intuitive. I go to a small public college and the course is much more formal and proof driven. These lectures are a great addition to (as well as a nice break from) formal proofs. Thanks MIT!

  • @mahneh7121
    @mahneh712110 ай бұрын

    Yes, he is light years beyond most teachers, especially because he has the right ways to make you understand. For example, if a full proof is too much, he gives an example to get the intuition. So you follow all the class.

  • @kstahmer
    @kstahmer12 жыл бұрын

    Thanks for pointing this out. Also, when vectors (1, 1, 2), (2, 2, 5) and (3, 3, 8) are written as column vectors and placed in a 3x3 matrix A, A’s first two rows equal (1, 2, 3). Hence the rank of A is 2 and its nullity is 3 - 2 = 1 > 0. Thus A’s columns are linearly dependent.

  • @bautistabaiocchi-lora1339
    @bautistabaiocchi-lora13394 жыл бұрын

    This lecture is amazingly put together. It feels like I am watching a well written movie, where all the pieces seem to fall into place. All this is thanks to the professor.

  • @MrYuiagaraki18
    @MrYuiagaraki188 жыл бұрын

    No other video about LA is better than this! respect and tks prof so much :)

  • @ArnavBarbaad

    @ArnavBarbaad

    8 жыл бұрын

    +Roku Vo But he never talked about Los Angeles in the whole video? =/

  • @MrYuiagaraki18

    @MrYuiagaraki18

    8 жыл бұрын

    LA is linear algebra not Los Angeles hahaha :v

  • @ceidass

    @ceidass

    8 жыл бұрын

    lol

  • @rickshawty
    @rickshawtyАй бұрын

    Thank you so much for making these lectures public and not gatekeeping knowledge.

  • @bfl9075
    @bfl90752 жыл бұрын

    28:43 A small mistake here. These three vectors are not the basis. (-v1 + 2v2 - v3=0)

  • @TimBate

    @TimBate

    2 жыл бұрын

    True. You can also look at the rows since the rank is the same for rows and columns. [1, 2, 3] = [1, 2, 3]. Everybody goofs sometimes.

  • @hurbig
    @hurbig3 жыл бұрын

    It is so satisfying when you struggle with linear algebra for a whole semester and then you watch these lectures and it all makes click. I bet it would be a bit harder to understand if this was the first time I heard about all these concepts because it's a lot to remember, but Gilbert Strang can explain why the rules we read in the textbooks are true very intuitively. Before I was able to solve exercises, now I am able to understand them.

  • @tungdinh3664
    @tungdinh36643 жыл бұрын

    Due to the pandemic, I have to take LA at a local community college online. And taking a course online meaning you are on your own, learning by only reading notes and textbook. Before Prof. Strang's lectures, I was struggling with the class. Now I understand the subject much better. Thank you, professor!

  • @Indik47
    @Indik4710 ай бұрын

    The best linear algebra teacher I`ve ever seen (and read, his book is great)

  • @easterPole
    @easterPole6 жыл бұрын

    This is just amazing, how much you appreciate this lecture largely depends upon how much you paused during the previous ones.

  • @BlackStarSeries
    @BlackStarSeries8 жыл бұрын

    He does the lecture off the top of his head, he's great

  • @egehancosgun5598
    @egehancosgun55984 жыл бұрын

    On 45:55 he says that any two linearly independent vectors would span the C(A). But these two linearly independent vectors should also be in C(A) he forgot to mention that i think. Because (1,0,0) and (0,1,0) are linearly independent but they do not span C(A). I listened carefully that part 3 times before writing this comment but maybe I missed it.

  • @jenkinsj9224

    @jenkinsj9224

    3 жыл бұрын

    exactly man, i had this question in my mind... hi-fi

  • @bigbrothersinnerparty297

    @bigbrothersinnerparty297

    2 жыл бұрын

    He says “and they span” at 46:01 but it is hard to hear

  • @tianjoshua4079
    @tianjoshua4079 Жыл бұрын

    I cannot help but write something laudatory after watching every video.

  • @encheng1136
    @encheng11368 жыл бұрын

    Very useful course! You can learn Linear Algebra yourself! Let knowledge spread to everyone, free and efficiently.

  • @pmshadow
    @pmshadow14 жыл бұрын

    Gilbert Strang, You are an awsome teacher! Congratulations for the great work done and thanks for the opportunity! Congratulations to MIT as well.

  • @omgitalo
    @omgitalo7 жыл бұрын

    This has been one my favorite lectures so far, for me really brought these concepts together beautifully for the first time.

  • @fernando2011
    @fernando20115 жыл бұрын

    This professor has saved me a bunch of struggle. I really appreciate it. I don't normally write on KZread videos but this is an exception. Great stuff, great professor. Can't wait to watch more.

  • @mahneh7121
    @mahneh712110 ай бұрын

    A good line from GPT3: In summary, if one of the columns of the matrix representing a set of vectors becomes all zeros after reduction, it means that one of the vectors in the set is the zero vector, and it can be expressed as a linear combination of the other vectors. This, in turn, indicates that the set of vectors is not linearly independent.

  • @yaboimdaro
    @yaboimdaro2 жыл бұрын

    Thank you MIT and Professor Strang for those fascinating lectures. In every lessons we reuse the things we have learned before and this makes a super connection between the topics. This lecture was a great example of that. Thank you again

  • @geenstagni1060
    @geenstagni10603 жыл бұрын

    I'm literally in awe of what I can understand thanks to Dr. Strang

  • @erazn9077
    @erazn9077 Жыл бұрын

    37:19 “Independence: that looks at combinations not being zero, Spanning: that looks at all the combinations, Basis: the one that combines independence and spanning, Dimension of a space: number of vectors in any basis ( cause all bases have the same number)“

  • @mohithjagalmohan
    @mohithjagalmohan4 жыл бұрын

    @28:35, the set of vectors given are not a basis. They don't span R^3 since the nullspace corresponding to those vectors have a common form: [c,-2c,c] which is not only the zero vector. But however, the intended idea is clear from whatever he has explained :)

  • @acadoe
    @acadoe4 жыл бұрын

    Best video I have watched so far, I was with him all the way and my concentration never dipped.

  • @supersnowva6717
    @supersnowva6717 Жыл бұрын

    This is just a perfect lecture, pure perfection! Can't thank you enough for explaining these concepts so clearly Professor Strang! I can listen to Prof Strang's lecture all day everyday!

  • @ashiskarmakar7060
    @ashiskarmakar70604 жыл бұрын

    Nice lecture sir.Love from India🇮🇳🇮🇳

  • @earltan739
    @earltan7395 жыл бұрын

    I'd just like to say thank you to Prof. Strang. The best prof I never had.

  • @prajwalchoudhary4824
    @prajwalchoudhary48243 жыл бұрын

    I was a bit confused after the last lecture but now it's clear why reduced row echelon form and rank are so important thanks professor

  • @jonaskoelker
    @jonaskoelker2 жыл бұрын

    My favorite example of two bases for the same space: in the old days your showers had two knobs that let you adjust cold and warm water (per time). Modern showers let you adjust volume per time (~= warm + cold) and temperature (~= warm - cold). For every configuration of temperature and volume per time, there is some setting of cold and warm that achieves that configuration, but it might be tricky to find. [Probably in practice this system is not linear. But it feels about right.]

  • @MattMacKinnon

    @MattMacKinnon

    Жыл бұрын

    It is an interesting idea.

  • @SharatS

    @SharatS

    Жыл бұрын

    It is an interesting idea.

  • @SharatS

    @SharatS

    Жыл бұрын

    It is an interesting idea.

  • @ziyaalim2800
    @ziyaalim28005 жыл бұрын

    Thanks so much for the lecture. Professor Strang is a teacher that devote his heart to educate people , thanks to him I have been progressing in the field of Linear Algebra.

  • @georgesadler7830
    @georgesadler78302 жыл бұрын

    DR. Strang thank you and MIT for another great lecture on classics linear algebra topics.

  • @fredhasopinions
    @fredhasopinions3 жыл бұрын

    woah this guy just singlehandedly saved this semester for me. and he does it so nonchalantly. i'm stunned

  • @abhinandankumar225
    @abhinandankumar2256 жыл бұрын

    "Any space with those vector in it must have all the combination of those vector in it. And if I stop there then I have got the smallest space and that is the space they span". Got a feel. ☺️ Amazing Person.

  • @rogeriojunior9459
    @rogeriojunior945910 ай бұрын

    this guy is awesome. i'm watching his classes now because i'm taking linear algebra 2, and my professor is chinese(i live in brazil) and is using strang's book to give a quit revision about linear algebra 1, so i came here to watch his playlist, and man how i wish i had watched this during the pandemic in 2020, just like i did with david jerison's calculus playlist

  • @timelordyunt7696
    @timelordyunt76965 жыл бұрын

    This video is amazing! AMAZING! All the principles fit reality so nicely! LONG LIVE MATRICES.

  • @amineech-cherif2386
    @amineech-cherif23869 жыл бұрын

    one of the best teacher in the world thank you professor Gilbert Strang god bless u

  • @sawscie3081
    @sawscie30819 жыл бұрын

    I can't expect enormous answers. Like it a lot.

  • @Marius-vw9hp
    @Marius-vw9hp3 жыл бұрын

    These lectures are actually fun! The book is also great. Thanks Gilbert.

  • @ba0w0w
    @ba0w0w11 жыл бұрын

    What a brilliant man.. I wish I had a teacher like that in all my courses!

  • @aarifhussain3700
    @aarifhussain37004 жыл бұрын

    No words for sir strang ,he is my favorite teacher

  • @RohitWason
    @RohitWason3 жыл бұрын

    Nicely done, prof! Some people are just good at Linear Algebra, some can make others be good at Linear Algebra!

  • @dampersand
    @dampersand12 жыл бұрын

    To come at this from the other direction, it is easy to see that the vectors in the second "basis" also fail to _span_ R^3 (the other necessary condition to form a basis). Any linear combination of the three vectors will be of the form (x,x,y), so the vector (1,2,3), for example, is not in the span of the set of vectors.

  • @jinzhonggu8276
    @jinzhonggu82762 жыл бұрын

    A lot equivalent propositions here, prof strang beautifully demonstrated that they are all connected with the basic eliminations process, it helps a lot.

  • @NisargJain
    @NisargJain5 жыл бұрын

    I NEED SOME SPACE AFTER THIS!!!

  • @dramon231
    @dramon23114 жыл бұрын

    my thanks to MIT for providing not only a proffesor whose interested in teaching.... but good at it.. and .. providing it for free. Some day.. i hope to attend thanks

  • @rajkamalingle9144
    @rajkamalingle914410 ай бұрын

    Note for myself : By basis for column space, we mean LI vectors which span the whole "column" space. Basis need not always be those [1 0 0], [ 0 1 0] type vectors. Basis is defined wrt a space as follows : It is the set of LI vectors which span that space.

  • @ozzyfromspace
    @ozzyfromspace3 жыл бұрын

    I actually consider Professor Gilbert Strang to be one of my heroes 🏆❤️🙏🏽🎊

  • @brandonnoll5527
    @brandonnoll55273 жыл бұрын

    This man is a literal God at teaching linear can he please teach my lecturer how to teach.

  • @zhijianhuang6802
    @zhijianhuang68029 жыл бұрын

    this guy is amazing

  • @gavilanch
    @gavilanch15 жыл бұрын

    But is still good that you say that now so we don´t get too confused. Thank you. And Thank you Gilbert Strang for this work!!!

  • @khadarosman3479
    @khadarosman34797 жыл бұрын

    Gilbert Strang greatest mathematics professor in 21st century.... Thank you a lot.

  • @ahmedbataweel9661

    @ahmedbataweel9661

    4 жыл бұрын

    he is a good but I disagree with being the greatest, I have seen other profs who come prepared to the lecture, you watch them like you watch Ted talk

  • @ManojKumardurai
    @ManojKumardurai Жыл бұрын

    I am grateful for seeing this video

  • @CKPSchoolOfPhysics
    @CKPSchoolOfPhysics3 жыл бұрын

    Your videos have been saviour for me. Thanks a ton dear prof ❤️

  • @infonothing7807

    @infonothing7807

    3 жыл бұрын

    yeah

  • @MrSnitsarenko
    @MrSnitsarenko3 жыл бұрын

    amazing lecture! the best lecture so far

  • @Harry-cs2zr
    @Harry-cs2zr4 жыл бұрын

    So glad you put these up

  • @martinsanchez-hw4fi
    @martinsanchez-hw4fi4 жыл бұрын

    This si such a treasure. Thank you so much.

  • @RosebudsRosebud666
    @RosebudsRosebud666 Жыл бұрын

    Thank you, MIT! And thank you for enabling comments! Free speech kicks ass!

  • @qixianggao3077
    @qixianggao30773 жыл бұрын

    The best linear Algebra teacher!!

  • @flavioagostini153
    @flavioagostini1533 жыл бұрын

    Lectures with my prof feel like fistfighting a grizzly bear, lessons with gilbert feel like being sung a lullaby by celine dion

  • @vishnavi19
    @vishnavi199 жыл бұрын

    Love your lectures. Thank you Sir

  • @andreww2319
    @andreww23194 жыл бұрын

    Intellectually stimulating and after just one drink you really hear the humor of this guy ... small example 44.10 ... "I guess I am giving you infinitely many possibilities so I can't expect a unanimous answer" ... LOL

  • @sambi246
    @sambi24611 жыл бұрын

    Disculpe no fue mi intención incomodar con mi comentario, al contrario estoy muy agradecido con los cursos. Bueno muchas gracias y espero que sigan colocando más videos. Saludos cordiales.

  • @NNCCCC63
    @NNCCCC63 Жыл бұрын

    Independence, Basis, and Dimension. Hmmm, sounds like a Robert Nozick title. Thank you Dr. Strang !

  • @stran1992
    @stran199212 жыл бұрын

    If you guys find the determinant of the matrix, it shows Det = 1*(16-15) - 2*(8-6) + 3*(5-4) = 0. So the matrix is not linearly independent.

  • @hasan0770816268
    @hasan07708162684 жыл бұрын

    independence: a bunch of vectors are independent if there is no such combination among them that gives zero (other than all-zero combination). reminder: pivots represent independent columns while free columns mean there is dependence. a bunch of vectors C in a matrix A are independent when the nullspace of Ac =0 happens only when C is all zeros, a matrix of independent columns will have a rank = n (number of columns). span: vectors v1...vl span a space when that space consists of combinations of those vectors. basis of a space is a sequence of vectors v1...vd that are 1. independent 2. span that space basis test: n vectors of subspace Rn give basis if the matrix made from those vectors is invertible. given a space (such as Rn) then every basis for that space has same number of vectors (n vectors), that is what we call "Dimension". so for a space(n) we have a matrix A where rank(A) = no. of pivot columns = dimension of space n

  • @ThePositiev3x
    @ThePositiev3x9 жыл бұрын

    Column space is span of pivot columns and dim(Colspace) (rank)= number of pivot cols BUT ! Even tough dim(nullspace) = number of free variables, nullspace is not span of free variable columns. Have I just get it right?

  • @yallaharabstna
    @yallaharabstna8 жыл бұрын

    just amazing! I feel a little bit sad because I have no chance to listen this course exactly from him :)

  • @ibrahimozcan4333

    @ibrahimozcan4333

    6 жыл бұрын

    hadi abi hadi şov yapma, direk ondan dinliyosun zaten

  • @moayadyaghi

    @moayadyaghi

    5 жыл бұрын

    You are attending his course for free, be happy

  • @suryapratapsingh7106
    @suryapratapsingh71062 жыл бұрын

    thank you Gilbert Sir

  • @Lemnirot
    @Lemnirot15 жыл бұрын

    The second basis for R^3 is not a basis, since -(1,1,2)+2*(2,2,5)=(3,3,8); i.e., the vectors are not linearly independent.

  • @manishkumarpal8912

    @manishkumarpal8912

    3 жыл бұрын

    Thank you

  • @eaatmyshorts
    @eaatmyshorts2 жыл бұрын

    This man has infinite chalkboards

  • @Viggen66
    @Viggen66 Жыл бұрын

    This professor is amazing

  • @rajeshreddy3133
    @rajeshreddy31335 жыл бұрын

    I don't why I am in Love with this Guy.

  • @imegatrone
    @imegatrone12 жыл бұрын

    I Really Like The Video Independence, Basis, and Dimension From Your

  • @abdelaziz2788
    @abdelaziz27882 жыл бұрын

    gilbert strang makes linear algebra fucking simple

  • @jockyitch8815
    @jockyitch8815 Жыл бұрын

    Thank you for the excellent lecture!

  • @emilfh
    @emilfh13 жыл бұрын

    Great Lecture!

  • @aymensekhri2133
    @aymensekhri21334 жыл бұрын

    thanks a lot Pro. Strang

  • @LAnonHubbard
    @LAnonHubbard11 жыл бұрын

    Thanks Prof. Strang.

  • @vishnums97
    @vishnums977 жыл бұрын

    how can we relate raws in calculating the dimension of the column space

  • @mikebull9047
    @mikebull90473 жыл бұрын

    same bug in the exmple as in pres 7, column 3 and 4 are combinations of 1 and 2, therefore, you have 2 independent 3d vectors, ie. they do not span the space. class in coma.

  • @samuelleung9930
    @samuelleung99304 жыл бұрын

    Just based on the lectures until now: we can’t just put a = between rank(A) and dimension of C(A) right? The number 2 may just „happens“ to be the same. We calculate the rank by finding the numbers of pivots with row elimination, which changes the column vectors and the eliminated column vectors are apparently not the linear combination of the original ones. Maybe I will figure it out in lecture 10.

  • @marcusofsillypoor187
    @marcusofsillypoor1875 жыл бұрын

    It is great that we could press the pause button to think, those "fortunate" students didn't have this luxury, hehehe... Yeah, they could still do that after lecture, of course... Internet is great and MIT is so generous to put all these lectures up for free viewing... Thank you very much

  • @matt17389
    @matt17389 Жыл бұрын

    Im not sure what is more impressive. What his talking about or that there is a professor strang. Yours sincerely matt strang

  • @jorgeribes2662
    @jorgeribes26624 жыл бұрын

    He is so slowly teaching, but is a wonderfull teacher.

  • @athenstube
    @athenstube10 жыл бұрын

    Great lecture. Thank you!

  • @ayushchakraborty4406
    @ayushchakraborty44063 жыл бұрын

    Professor Strang said that the span of any vectors is the smallest subspace, I didnt quite get that. Would appreciate if anyone helps me on that regard, but nonetheless, this is a gem of a lecture, Thanks professor Strang.

  • @ryanchiang9587
    @ryanchiang95877 ай бұрын

    basis lneear combination vector space subspace linear transformation

  • @yashushukla8078
    @yashushukla8078 Жыл бұрын

    For the last example why did we not convert the matrix to reduced row form.....and then find the pivot column? Find converting column 2 and 4 are the free column......

  • @xyber3364
    @xyber336414 жыл бұрын

    very good teacher, very helpful video