Linear subspaces | Vectors and spaces | Linear Algebra | Khan Academy

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  • Опубліковано 7 жов 2024

КОМЕНТАРІ • 299

  • @AdhikariMohan
    @AdhikariMohan 11 років тому +72

    Amazing..I spent past 7 hours trying to understand subspaces from my notes with no success and now its crystal clear in just 23.5 minutes. A huge THANKS to You!!

  • @tauceti8341
    @tauceti8341 9 років тому +425

    + V is a subspace (0-6:00)
    - V contains the 0 vector: (2:26-2:44)
    - Closed under multiplication: (2:47-4:23)
    - Closed under addition : (4:28-5:35)
    Subspace 3 points ; subspace & closure under (A & M)
    Examples using concepts:
    proving a subset (S) is/not a subspace - (08:55-14:17)
    Span (v1, v2, v3) is a valid subspace of R^n? - (14:21-19:42)
    Visualizing if a simple vector can be a subpsace. U = span([1, 1]) (19:43)

  • @VineetontheBeat
    @VineetontheBeat 12 років тому +30

    This is so good. Teachers usually go straight into complex examples and totally roll over the concepts. You make the concepts clear and concise. Thanks so much!

  • @Shy_Guy11
    @Shy_Guy11 11 років тому +22

    In addition to that, he is great at explaining all these concepts to people who have little or no idea about the subject. Most people don't realize this, but this is extremely difficult to do for most people, but he is able to get into the mindset of a person who is new to this stuff, and explain it in such a way despite his great understanding of the subject. Thank you Sal for all your hard work..

    • @rahulkiroriwal8779
      @rahulkiroriwal8779 3 роки тому +1

      hello there , how are u . its been 8 years

    • @romeo5239
      @romeo5239 7 місяців тому

      ​@@rahulkiroriwal8779 now 11

  • @yangvely7018
    @yangvely7018 7 років тому +549

    You are better than my professor lol. I dont know why I attend college.....

    • @7thFormVoid
      @7thFormVoid 5 років тому +36

      So you can get a real degree?

    • @That_One_Guy...
      @That_One_Guy... 5 років тому +23

      Yeah, to get degree so you can get a job, that's so annoying

    • @Nomnomnom165
      @Nomnomnom165 5 років тому +14

      @@That_One_Guy... I'm in college and the companies I'm aiming for don't need degrees. They're just insanely hard for everyone to get into

    • @codingtheworld674
      @codingtheworld674 5 років тому +10

      If you are just learning mathematics in your college, so you don't need to go. We should not be in college just for a degree paper, do more things(-like starting a new projects,etc.)...

    • @daehwankim4246
      @daehwankim4246 4 роки тому +1

      ㅇㅇ

  • @dalisabe62
    @dalisabe62 2 роки тому +3

    I love his style and voice. His detailed persistent explanations show how much he is capable of relating to his audience and how much experience he has in teaching. I found him the best explainer that is out there for concepts that are typically confusing or need further breakdown.

  • @Hemenmyname
    @Hemenmyname 10 років тому +20

    I personally am thankful for your service sir, thank you very much.

  • @ypenburger
    @ypenburger 11 років тому +154

    me looking in my linear algebra book: dafuq???
    me looking in the same book after a video from khanacademy: Aha!

  • @Sundoren
    @Sundoren 10 років тому +15

    superb voice superb explanation superb colors why we dont have teachers like u damn

  • @lolalukie713
    @lolalukie713 12 років тому +22

    you accomplished in 23 mins what my linear algebra prof couldn't in two 2 hour lectures.

    • @rahulkiroriwal8779
      @rahulkiroriwal8779 3 роки тому +2

      hey how u doing , its been 8 years ?

    • @lolalukie713
      @lolalukie713 3 роки тому +16

      @@rahulkiroriwal8779 I have my degree in Mechanical Engineering and am working as a project engineer for construction projects and have started a business on the side ! Thanks for checking :D

    • @bookman9897
      @bookman9897 3 роки тому +1

      @@lolalukie713 wow really great keep growing

  • @Hepichack
    @Hepichack 10 років тому +5

    Congratulations man !!!
    They way you teach is very clear-easy-good,not only because you explain them with great way,but because you used examples,and you used Cartesian plane to show how vectors works in reality. That really helps,because to understand something in maths,you need to implement it. Keep the good job !!!

  • @devilpizza123
    @devilpizza123 13 років тому +1

    thanks! my lecturer is terrible at explaining this stuff and uses all the extremely abstract notation stuff that no body understands. your explanations are easy to understand and make difficult to grasp concepts simple. i love it!

  • @LAnonHubbard
    @LAnonHubbard 14 років тому +5

    Very cool explanation. I've been trying to teach myself this sort of stuff from books and Wikipedia. They're too dry for my current level of knowledge. Your dynamic presentation is exactly what I need and I'm sure will help me to understand other resources.

  • @cwruhsk5
    @cwruhsk5 14 років тому +2

    Wow..... I spent five hours trying to learn this, and still could not comprehend the material. 20 minutes of this video, and everything makes sense now. This is awesome!!!

  • @neomarc9946
    @neomarc9946 7 років тому +27

    Thank you sir for making it 100% easier. My professor sucks af.

  • @snake10566
    @snake10566 11 років тому +3

    The way you define everything in simplistic terms is amazing. Thank you so much.

  • @fukgovernment
    @fukgovernment 10 років тому +62

    You deserve a noble price. Thanks

    • @anonymoose8829
      @anonymoose8829 10 років тому +12

      Nobel Prize? :P

    • @inteusproductions
      @inteusproductions 10 років тому +29

      Nolen Lah Nope, just a noble one

    • @Sundoren
      @Sundoren 10 років тому +1

      inteusproductions :DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD

    • @StephenRayner
      @StephenRayner 9 років тому +2

      inteusproductions Haha, he sure does, but none are given for teaching.

  • @fuzzybuns1234
    @fuzzybuns1234 10 років тому +10

    Hey Sal,
    I looooove your videos, first of all. After taking Algebra 1 I told myself I would spend one summer learning all through Calc 1, and, thanks to you, this summer I am attending SacState as a Freshman in high school. I know that this topic is unrelated to the video and that you probably won't even have time to read this, but I was wondering if you have any intuition that you could teach me regarding visualization of Lie groups and symmetries because it's really difficult for me to imagine. I understand how group theory works, but imagining these things as circles and large manifolds is a giant leap from just sets of numbers. Thanks a ton for your videos; I don't know what I would have done without you.

    • @awesomecodeyay8382
      @awesomecodeyay8382 2 роки тому +1

      Nice, I did calc 3 and Diff Eq in 8th grade. I also attended USAMO.
      Are you a full time student at the university, or are you just taking some courses there? I don't think you can graduate high school right in just one summer. Also, I'd imagine that there are gaps in your mathematical knowledge because you haven't done enough geometry, and you did not spend enough time on the prerequisites of calc.
      Additionally, doing higher math does not mean a lot. I did Calc BC in school as a 7th grader, and I don't consider my 7th grade self all that smart. Doing calc does not require as much creative thinking as math competitions.
      Try the first competition to the IMO, which is the AMC 10/12. Try some problems there and see how you do. This competition will probably be hard for someone without much experience. Next, there will be the AIME, which is much much harder. If you want to be better at math, I suggest participating in these competitions.

  • @enjoyablesounds
    @enjoyablesounds 14 років тому +1

    Thank you sal, you are a great example of a good human being. With all negativity around the world you give me hope. Thank you so so much :)

  • @0dablkin0
    @0dablkin0 11 років тому +3

    Thank you very much, my professor is blowing through this information leaving me wondering what just happened, you are helping me keep pace with the lessons

  • @makavelic2000
    @makavelic2000 11 років тому +1

    I LOVE YOU. This helped so much. was freaking out about this class and was about to drop it, but now i understand enough to not panic.

  • @bryancolon5090
    @bryancolon5090 3 роки тому +4

    Thank you so much. When you stated between 5:10-5:30 that we're simply choosing vectors within the given parameters of our space V and then adding them together to see if the resultant vector was still in space V, everything finally clicked. I immediately understood what "closed under addition" and "closed under scalar multiplication" meant. Words cannot describe my gratitude! Thank you!

  • @sauryashrestha
    @sauryashrestha 8 років тому

    I highly recommend this video. The presence of a graph makes it much easier to comprehend!

  • @TheBananahulk
    @TheBananahulk 8 років тому +180

    Haha if you look at the statistics. The viewer count always goes up before exam periods :P

    • @laartisticfellow2382
      @laartisticfellow2382 5 років тому +2

      Im a student of statistics and i can vouch for that

    • @Iluminent
      @Iluminent 5 років тому +4

      crazy thought you got there, I wonder why that is...

    • @Xxjorgex123
      @Xxjorgex123 5 років тому +9

      how you figured that out genius?

  • @rapid1010
    @rapid1010 5 років тому +1

    You're presentations are very clear and you're a great teacher as well.Thank you very much for these videos!

  • @ocsantiago
    @ocsantiago 14 років тому +2

    This is great. I just discovered your library as well. Great stuff!!

  • @phalgunvedantam1388
    @phalgunvedantam1388 6 років тому

    Thanks to sal i now understand everything about basis, vector spaces and every other thing right before my tomorrow's exam... Thanks sal

  • @AvengedRocker92
    @AvengedRocker92 13 років тому +1

    Really helped out, thanx for the video!

  • @SoloPro
    @SoloPro 8 років тому +1

    Seriously this explanation was good im so happy i typed it in youtube... defo liked and subbed

  • @AdamBr-q8d
    @AdamBr-q8d 11 місяців тому

    You are a life saver, thank you! I fully understand it now.

  • @sarveshc2985
    @sarveshc2985 Рік тому

    wow what an amazing explanation! I spent too much time looking in notes and couldn't get much out of it

  • @alejandromunoz8086
    @alejandromunoz8086 6 років тому

    You explained to me in under half an hour wait University professor can't explain in 3 lectures. Thank you so much, I understood a hole section in this video

  • @IndulgeObscenity
    @IndulgeObscenity 14 років тому +1

    You are truly a great teacher! Than you for the posting!

  • @fuahuahuatime5196
    @fuahuahuatime5196 11 років тому

    Wow, thank you SOO much! My teacher did a HORRIBLE job explaining this. I've tried searching everywhere on youtube... Thanks man! Seeing it visually helps a lot more than just seeing the theorems or whatever proven with random variables with no significance.

  • @EchoL0C0
    @EchoL0C0 11 років тому +1

    Thank you so much for taking the time to make this video! I really appreciate the fact that you take the effort to try to connect these concepts in many different ways, like in terms of things we've already learned, or what works and what doesn't, instead of just the formal mathematical definition. I mean, appreciate the formal mathematical definition, (I like math because it seeks "truth without error") but it's not much use if I don't understand things in the first place. Anyway, thanks!

  • @preciousgeofrey6192
    @preciousgeofrey6192 Рік тому +1

    More gratitudes should be granted to you Sir

  • @nturner4
    @nturner4 14 років тому

    wow this is awesome. this is SO much more helpful than any lecture I've been to this year!

  • @MrSauce714
    @MrSauce714 13 років тому

    Linear algebra test tomorrow not worried about this topic thanks to you!!!! Great vid!!

  • @deathmachine91
    @deathmachine91 11 років тому +2

    You are a better teacher than my professor. Thanks for putting the video up

  • @beanfant_jesus
    @beanfant_jesus 5 років тому +1

    You taught me in 25 minutes what my professor took 2 hours to cover in class. Thank you!

    • @codingtheworld674
      @codingtheworld674 5 років тому +1

      it is not the first time you have been facing like that a new subject, so that you understood in 25 min.

  • @hellokat68
    @hellokat68 10 років тому

    thanks so much, you help me learn all these math concepts that I were unable to grasp in class when I was in school

  • @techtalentblueprints
    @techtalentblueprints 2 роки тому

    You are great. Now this concept is clear crystal for me.

  • @abdulrahman226
    @abdulrahman226 11 років тому

    dude, Partrick is good and khan is good, they r different in their styles. khan is the very best in explaining the derivation and the origin of things, partick is gr8 in solving examples.

  • @mohammedsaeed4814
    @mohammedsaeed4814 8 років тому +1

    thanks

  • @예밤-f3k
    @예밤-f3k 3 роки тому +1

    this was such a great review before my first test

  • @chvere123
    @chvere123 14 років тому

    it really saved me time for understanding these materials, thanks a lot.

  • @Adam-gp3ij
    @Adam-gp3ij 5 років тому

    That’s pretty clear! Thank you

  • @rochelletarin6422
    @rochelletarin6422 3 роки тому

    Well, this made more sense than my teachers lecture. Thank you!

  • @danielgonzalezisaiev9643
    @danielgonzalezisaiev9643 11 років тому

    I'm learning crazy much! You already feel like my best friend dear khan academy mystery man.

  • @aandha1
    @aandha1 13 років тому

    This guy is just unbelievale !! Thumbs upp!!!

  • @danielgibbons301
    @danielgibbons301 4 роки тому +1

    CLEARLY!

  • @A-003
    @A-003 14 років тому

    Thanks you VERY MUCH for the nice, simple, useful explanation. God bless you

  • @shishenliart
    @shishenliart Рік тому

    I think of it as a subset being an open community of vectors whereas a subspace is a closed community of vectors.
    Since you can have a subset of Rn without it being closed under multiplication or addition or having the zero vector since it can span some or all of Rn. However, to get a subspace, you have to have it be in a subset that satisfies having the zero vector, closed under addition and multiplication.

  • @fathimahida8878
    @fathimahida8878 6 років тому

    it really helped me... thanku soo much...keep uploading more vedios...

  • @wesKokigen
    @wesKokigen 13 років тому

    THanks! It makes so much sense now.

  • @stephaniepaul2010
    @stephaniepaul2010 11 років тому

    crazy to think i'm paying £9k a year tuition fees, but learn the course from these videos! Thankyou! :)

  • @timgoppelsroeder121
    @timgoppelsroeder121 5 років тому

    Thank you for these tutorials. They are very compact

  • @omertopchi2280
    @omertopchi2280 8 років тому +1

    Thank you so much!

  • @darrowshire11
    @darrowshire11 13 років тому

    Perfect! Just what i needed! Thx alot

  • @japierdoleokurwa
    @japierdoleokurwa 12 років тому

    @123aellis in example (x1 in R and x1>0, x2 in R) this will be a subspace if any c that is in real set will satisfy above conditions. Your 'c' does satisfy condition -> v[2,4]*3=[6,12]. 6 is greater than 0. However -3 will product vector [-6,-12]. -6 does not satisfy condition x1>0. Important is that it must be valid for any c's in R.

  • @yoursoothingmusic1754
    @yoursoothingmusic1754 3 роки тому

    thanks. you took 30 mins to to untwine the confusion my professor infused in me for one semester

  • @Msmotionocean
    @Msmotionocean 9 років тому +1

    Thanks! This is amazing!

  • @marygraceadolfo8782
    @marygraceadolfo8782 4 роки тому +1

    You're very kind, sir. Thanks

  • @diz8344
    @diz8344 6 років тому

    Thanks, it really helps me a lot.

  • @jaker9007
    @jaker9007 3 роки тому

    Best tutorials on linear algebra!

  • @homestar92
    @homestar92 13 років тому

    These videos are teaching me more than my professor does. You may be saving my grade.

  • @amangoel8724
    @amangoel8724 4 роки тому

    thanks buddy you made my day

  • @Linkmarth
    @Linkmarth 13 років тому +1

    thank you so much

  • @DEEPAKSINGHcreative
    @DEEPAKSINGHcreative 5 років тому

    In summary, In order to define subspace using vector we need to define for R^n i.e. for all real value, exculding a certain ranges would bring up the possibilty of subset instead of subspace, SPAN by default are defined for R, hence they automatically fall into subspace cateogory. If there is any example that doesn't include R i.e real domain, please do provide. I think one you have mentioned would be n dimension zero vector, the addition or linear combination again results in zero vector, which is exception of trend, but for non-zero n-dimensional vector space to be termed as subspace, it needs to be defined for 'R' .
    Note: Here R represents real domain.

  • @Andradam33
    @Andradam33 14 років тому

    Making up where my prof lacks - every time. Thanks for your useful explanations and videos.

  • @dca24100
    @dca24100 12 років тому

    I feel ya. We're using that book here as well.

  • @violalagonigro-m4d
    @violalagonigro-m4d 11 місяців тому

    Single-handedly saving my life

  • @sheralikhtk5200
    @sheralikhtk5200 4 роки тому

    thanks ALOT u saved me

  • @teddybeitler
    @teddybeitler 14 років тому

    once again, you have saved me. thank you sir!

  • @eshaghazali2482
    @eshaghazali2482 5 років тому +4

    I have a quiz tomorrow God bless you sal!! 😭

  • @sanyamyadav2806
    @sanyamyadav2806 11 років тому

    GREAT IT IS.

  • @kushagrakalla7933
    @kushagrakalla7933 7 років тому

    It helped a lot

  • @michellezhuang2483
    @michellezhuang2483 4 роки тому +1

    For the example of whether U=span{v_1, v_2, v_3} is a subspace of R^n, don't v_1, v_2, and v_3 also have to have n components, as in they are a subset of R^n?

    • @michellezhuang2483
      @michellezhuang2483 4 роки тому

      Other than that, your video helped clear everything up. Thank you!

  • @empirewhite
    @empirewhite 7 років тому

    Thank you, you are the best!

  • @wonkamobil
    @wonkamobil 14 років тому +1

    Thanks a ton for the video, hopefully i'll pass my final because of this lol

  • @DFsdf3443d
    @DFsdf3443d 6 років тому +1

    would it then be correct to say that: Any linear combinations of vectors in a subspace must be equal to a vector that is also in the subspace ?
    kind of like the closure under addition? just with linear combinations?

  • @j0shda116
    @j0shda116 3 роки тому

    I was completely lost before watching only 25 seconds on this video.
    now I am a linear algebra prof

  • @Anonymoose123456789
    @Anonymoose123456789 11 років тому

    A scalar is any number contained within the real numbers, which includes zero and every single positive and negative number. That also includes all of the fractions and decimals.

  • @_dkta
    @_dkta 14 років тому

    Wow...very well explained!

  • @aranyak1881
    @aranyak1881 Рік тому

    Amazing, you teach 10 times better than my school does, god this world is weird.

  • @Recordingization
    @Recordingization 3 роки тому

    Nice class!

  • @rahalrsh
    @rahalrsh 13 років тому

    great video! thanks..

  • @petraalyousifi1472
    @petraalyousifi1472 2 роки тому

    thanks for saving my life

  • @judyhayun1102
    @judyhayun1102 3 роки тому +1

    is a point(that is not equal to zero) also a subspace? If we think of it as a position vector, it actually passes through the origin. that's why I'm curious

  • @legendkiller376
    @legendkiller376 9 років тому

    Khan you are a great man

  • @bsvshashanka6055
    @bsvshashanka6055 3 роки тому

    wah!!
    superb video

  • @Bumperpegasus
    @Bumperpegasus 13 років тому

    And you are officially my new teacher

  • @siddharthaganguly9286
    @siddharthaganguly9286 6 років тому +1

    Sal really enjoyed proving 0 vector is a subspace XD , great lesson as usual , keep doing it

  • @cnjaify
    @cnjaify 12 років тому

    thank you sir. u should receive like a humanitarian award for the number of times u have saved my life lol

  • @issaminasyan3143
    @issaminasyan3143 8 років тому

    Thank you Sal !!

  • @Powd3r81
    @Powd3r81 12 років тому

    I'm excited for this video

  • @nqvietanh343
    @nqvietanh343 13 років тому

    If I have Khanacademy on youtube, what is the point of staying in my math class? Well, I have more time to study other classes! Yay!

  • @Crystalwaa
    @Crystalwaa 15 років тому

    thank you so much!!!!! great explaination =D

  • @bandrukesucks
    @bandrukesucks 8 років тому

    This could be very useful for RNGs...

  • @TheRealChinOfKimJongUn
    @TheRealChinOfKimJongUn 6 місяців тому

    This explained more in 20 mins (10 with playing it on double speed) than my college prof did in an 1.25 hrs...