Subspaces are the Natural Subsets of Linear Algebra | Definition + First Examples

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  • เผยแพร่เมื่อ 5 ต.ค. 2024
  • A subspace is a subset that respects the two basic operations of linear algebra: vector addition and scalar multiplication. We say they are "closed under vector addition" and "closed under scalar multiplication". On a subspace, you can do linear algebra! Indeed, a subspace is an example of a vector space. We see that all of R^n, {0}, and lines through the origin are all subspaces, but that lines NOT through the origin are not subspaces.
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ความคิดเห็น • 54

  • @wei4448
    @wei4448 3 ปีที่แล้ว +28

    This is by far the most elucidated linear algebra course series that I've ever taken.
    All my previous teachers were not actually teaching linear algebra, they were just teaching computational rules and never explained the notion or the idea behind it even in a graduate school level, so, it was hard for me to relate linear algebra with other realms of science.
    Thank you!

    • @DrTrefor
      @DrTrefor  3 ปีที่แล้ว +3

      Glad they are helping!

  • @howtoshotbow6961
    @howtoshotbow6961 4 ปีที่แล้ว +28

    Thank you! My linear algebra teacher just introduced this topic using theorems and didn’t even explain what it represented. This helped!

    • @DrTrefor
      @DrTrefor  4 ปีที่แล้ว +3

      Glad it was helpful!

  • @shawcampbell7715
    @shawcampbell7715 2 ปีที่แล้ว +3

    Dear education system,
    Please make sure your seatbelt is on, the best teachers in the world are now able to teach the entire planet.
    It's ridiculous how good Dr Trefor is ; )

  • @stephen3418
    @stephen3418 2 ปีที่แล้ว +5

    This is such a captivating introduction into why we use subspaces (because we now have vectors in our life) and why they must follow the 2 closed rules. Thank you for this great video!

  • @mustafamarvat863
    @mustafamarvat863 4 ปีที่แล้ว +3

    i have search a lot on youtube and thanks god , finally i got you sir .

  • @muyangyan
    @muyangyan 3 ปีที่แล้ว +5

    This is an awesome explanation! Great visualization.

    • @DrTrefor
      @DrTrefor  3 ปีที่แล้ว +2

      Glad you liked it!

  • @donlansdonlans3363
    @donlansdonlans3363 4 ปีที่แล้ว +6

    Thanks god I found your channel, you deserve more subs

  • @israelogunmola1113
    @israelogunmola1113 3 ปีที่แล้ว +4

    This Is a Great TEACHER!!!

  • @nikitathakur5721
    @nikitathakur5721 6 ปีที่แล้ว +3

    Thank you sir
    It makes the concept more clear and easy

  • @sdagupat1
    @sdagupat1 ปีที่แล้ว

    This is absolutely wonderful explanation of vector spaces !!
    Man… it clarified so many things for me.

  • @rickykim3027
    @rickykim3027 4 ปีที่แล้ว +1

    such a helpful video that is explained in such an organized, enthusiastic and pedagogical manner! Thanks for the help!!

  • @elonak1529
    @elonak1529 3 ปีที่แล้ว +1

    Your channel is so underrated

  • @kathirs1
    @kathirs1 5 ปีที่แล้ว +2

    Awesome explanation. Thanks Dr.Trefor !

  • @bhavneetsingh4784
    @bhavneetsingh4784 4 ปีที่แล้ว +2

    Thank you so much for this wonderful explaination.

  • @jingyiwang5113
    @jingyiwang5113 7 หลายเดือนก่อน

    Thank you so much for this amazing explanation about subspaces! It is really helpful!

  • @umitsedgi
    @umitsedgi 3 ปีที่แล้ว +2

    I love your work! Thanks a lot for all your help here.

    • @DrTrefor
      @DrTrefor  3 ปีที่แล้ว +1

      Happy to hear that!

  • @pedrocolangelo5844
    @pedrocolangelo5844 2 ปีที่แล้ว

    This man is a truly hero.

  • @xingyubian5654
    @xingyubian5654 4 ปีที่แล้ว +1

    Thanks for the concise explanation.

  • @rajkumardongre3085
    @rajkumardongre3085 2 ปีที่แล้ว

    Really great explanation, love from India

  • @braa194332
    @braa194332 3 ปีที่แล้ว

    Thanks your doing the world a service.

  • @valentinx1107
    @valentinx1107 11 หลายเดือนก่อน

    Thank you for this awesome video!

  • @Ravi_Raj_ISM
    @Ravi_Raj_ISM 3 ปีที่แล้ว +1

    thanks a lot sir. also thanks miss ism who shared this video :)

  • @AbhishekYadav-jv7eu
    @AbhishekYadav-jv7eu 3 ปีที่แล้ว +1

    Great video

  • @SanaZub
    @SanaZub 3 ปีที่แล้ว +1

    thank you

  • @imn2058
    @imn2058 2 ปีที่แล้ว +1

    you are awesome!

  • @mattl6886
    @mattl6886 4 ปีที่แล้ว

    Very helpful! Thank you.

  • @jasjclement
    @jasjclement หลายเดือนก่อน +1

    Thanks

    • @DrTrefor
      @DrTrefor  หลายเดือนก่อน +1

      Thanks so much!!

  • @Realisation404
    @Realisation404 3 ปีที่แล้ว

    In the subspace example of a line not passing through the origin, we took the two vectors x and y not belonging to S subspace ,but shouldn't we take x and y vectors belonging to S and then check the conditions.

  • @samuelessuman4726
    @samuelessuman4726 3 ปีที่แล้ว

    Thank you Sir❤❤❤❤

    • @DrTrefor
      @DrTrefor  3 ปีที่แล้ว

      You're most welcome!

  • @afiqahjumali6308
    @afiqahjumali6308 3 ปีที่แล้ว +1

    May i know, what is the application of subspace? 🙏🙏 I hope someone can answer me cause i desperately need the answer

  • @ozodbekjuraev9268
    @ozodbekjuraev9268 4 ปีที่แล้ว

    thank you bro

  • @ngato5780
    @ngato5780 4 ปีที่แล้ว +1

    Are the vectors v = (−1,3,2) and w = (2,−2,4) orthogonal in R4?

    • @muhammadusman5521
      @muhammadusman5521 2 ปีที่แล้ว +1

      It has been two years
      I'm thinking should I answer or not
      😂

  • @pipertripp
    @pipertripp 3 ปีที่แล้ว +1

    So will a subspace always have at least 1 fewer dimensions than the original space? If the vector space is R2 then must the subspaces be 1 or 0 dimensions?
    If the spaces is a space of functions, say polynomials of degree

    • @DrTrefor
      @DrTrefor  3 ปีที่แล้ว +2

      It is a theorem that all the sub space of two dimensional plane are the origin, lines through the origin, and the entire plane itself.

    • @pipertripp
      @pipertripp 3 ปีที่แล้ว

      @@DrTrefor sure enough, ran into that in my text (Applied Linear Algebra by Olver and Shakiban) not long after watching this vid.

  • @puturnamehere777
    @puturnamehere777 4 ปีที่แล้ว

    Hi Professor Trefor, I’m a little confused. In the first line example with the line that passes through the origin and satisfies all conditions (around 3:30ish), you said that if we add vector x to a vector y it will be on the green line so I guess still an element within the sub space. But aren’t we assuming that x and y in this case are just scalar multiples of each other? What if they weren’t? Then no combination of x and y would fall on the line? Alternatively, if S is defined to be the entire Cartesian plane, then I guess we could then say that it satisfies all three conditions? I’m sorry if my question is long and confusing!

    • @VFORVICTORY1000
      @VFORVICTORY1000 3 ปีที่แล้ว

      if subspace just on that green line ->my opnion

  • @devkumar9889
    @devkumar9889 3 ปีที่แล้ว +1

    My teacher just taught numericals so I didn't understood 😂
    Thank u

  • @muhammadusman5521
    @muhammadusman5521 2 ปีที่แล้ว

    so it means that there are only two possible subspaces that are possible in 2d and one is the zero and the other is the whole xy plane

  • @suprememaster1951
    @suprememaster1951 2 ปีที่แล้ว

    Every subspace of R5 that contains a nonzero vector must contain a line. Is this statement true?

  • @seckinkarakoc7767
    @seckinkarakoc7767 4 ปีที่แล้ว

    I wonder if subset contains the vector 0 or the subspace of 0 then the subset itself a subspace ? Thank you!

  • @spacedustpi
    @spacedustpi 5 ปีที่แล้ว

    Thanks for the tutorial. Going to your example of the line (subspace) that does not go through the origin, you satisfy the 1st property by multiplying any vector on the line by zeros (is that right? has to be at least two zeros, depending on n dimensions?) you get the zero vector. I'm having trouble seeing this. This scalar multiplication certainly gives you a zero vector which is (0, 0), but how is this in the subspace? The origin does not lie on this line, so it actually still fails the first test. The way I see this, is that you are actually creating a zero vector on the line, but how do you describe this with coordinates? Do you define it as a vector (or point) on the line with no initial point, only a terminal point? Or vice versa?

    • @spacedustpi
      @spacedustpi 5 ปีที่แล้ว +1

      @@DrTrefor I misunderstood the second property completely. Multiplying any vector on the line by the scalar zero gave you a zero vector, and I thought this 'somehow' satisfies the first property. I realized that even though we get a zero vector, it is outside this line, so the first property remains unsatisfied. This is an epiphany of sorts after thinking about this for two days. Thanks.

  • @doggiegirls
    @doggiegirls 5 ปีที่แล้ว

    Thanks

  • @mathadventuress
    @mathadventuress 3 ปีที่แล้ว

    I still don’t get it :(

  • @Learn-jz1sc
    @Learn-jz1sc ปีที่แล้ว

    0:10