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Subspaces and Span

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  • čas přidán 25. 03. 2019
  • Now that we know what vector spaces are, let's learn about subspaces. These are smaller spaces contained within a larger vector space that are themselves vector spaces.
    Script by Howard Whittle
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Komentáře • 131

  • @dominiquedewet3311
    @dominiquedewet3311 Před 5 lety +217

    No professor of mine is able to compete with your brilliant explanations. Something seemingly complicated made so simple.

    • @damiankarsyn9653
      @damiankarsyn9653 Před 3 lety +1

      i guess it is pretty randomly asking but does anyone know a good place to watch newly released series online?

    • @biglexica7339
      @biglexica7339 Před 2 lety +2

      @@damiankarsyn9653 no

    • @andrewkorsten2423
      @andrewkorsten2423 Před 10 měsíci

      @@damiankarsyn9653 what series?

    • @GoldenTiger01
      @GoldenTiger01 Před 6 měsíci +2

      @@andrewkorsten2423 Fourier series?

  • @republicraider8336
    @republicraider8336 Před rokem +62

    You've just explained in 5 minutes what took my professor four weeks to half explain. Thank you.

  • @alish2001
    @alish2001 Před 4 lety +170

    I literally have a midterm in 2 hours you are a godsend

  • @linnsandvik6308
    @linnsandvik6308 Před 3 lety +22

    I really appreciate that you are speaking so clearly! It makes your videos easy to follow despite my hearing loss:)

  • @andrewkorsten2423
    @andrewkorsten2423 Před 10 měsíci +4

    I am just doing video 33. I went to the last ones to check out whether the quality is going out, or the topics are too complex. But every video has only positive comment, which are clarly not farmed. IT's clear that the series is highly effective in teaching us the bascis. I am brushing up on math overall, and it feels great to be doing this course.

  • @noahbarrow7979
    @noahbarrow7979 Před 3 lety +29

    this linear algebra playlist of yours is the absolute best i've come across on the internet. Thank you for being so lucid and lending so much clarity to these (sometimes) abstract concepts. Are you making a differential equations playlist? Would love to see some ODE!!

    • @ProfessorDaveExplains
      @ProfessorDaveExplains  Před 3 lety +16

      Yes I've been meaning to do that for a while! Just looking for the right writer.

    • @tejasgowdakr4700
      @tejasgowdakr4700 Před 2 lety +1

      @@ProfessorDaveExplains pls do PDE also (love from india )

    • @thedoc6413
      @thedoc6413 Před rokem

      @@ProfessorDaveExplainsdo you still plan on doing this?

  • @enweremfavour5315
    @enweremfavour5315 Před 2 lety +7

    You have made algebra easier for me compared to our boring lecturers. Thanks a lot. Much love ❤️ from Nigeria 🇳🇬

  • @zandertaljaard5431
    @zandertaljaard5431 Před 3 měsíci +1

    Note to viewers:
    The vector space V (as in the video) is also a subspace of itself.
    Hence, S does not have to be strictly smaller than V, as Dave slightly misleadingly stated in the introduction.

  • @zeffdronin6422
    @zeffdronin6422 Před 3 měsíci

    you really a gem. i cannot express enough gratitude for your videos, and im certain im not the only one to feel this way. thank you!

  • @snpthompson
    @snpthompson Před rokem +3

    you are the best! i hope you continue to upload these videos because you are the best teacher i’ve had! i know that so many others you have helped would agree

  • @neham1008
    @neham1008 Před rokem +1

    bro you are the best at teaching this. I'm sooo grateful for your videos. Thank you so much! I was stressing out like crazy for my upcoming quiz until I came upon your teaching videos.

  • @PrawjektSilvia
    @PrawjektSilvia Před 4 měsíci

    I think it's important to note that a subspace must also contain the additive identity. In the case of vectors, it must contain the zero vector. Great video!

  • @annaduong9830
    @annaduong9830 Před 3 lety +9

    I did love this vid so much. It helped me to understand the basis of vector spaces which had taken me a lot of time to learn in the class.

  • @anas8296
    @anas8296 Před 8 měsíci

    in 5 minutes , you have perfectly explained what my professor failed to teach us for 4 hours, much appreciated

  • @arnavkanathia757
    @arnavkanathia757 Před 3 lety +1

    great professor just teaching complicating things with such ease

  • @user-fy2ud4fq4g
    @user-fy2ud4fq4g Před 6 měsíci +2

    5:12 what if we multiplied by a negative scalar? Would we still get a matrix in the specified form?

  • @manishbhanga
    @manishbhanga Před 4 lety +23

    What if c is negative?

    • @Christian-mn8dh
      @Christian-mn8dh Před rokem +1

      exactly what I was thinking

    • @arwaomer9795
      @arwaomer9795 Před rokem

      Me too😅

    • @endabenson701
      @endabenson701 Před rokem +5

      Think it still works cause the bottom will be positive and the top will be negative, in other words, the bottom is the negative of the top line which is negative. A bit confusing but I think the rule he stated was that the bottom line is the negative of the top line, not that the bottom line itself is necessarily negative.

    • @hiteshpaul4093
      @hiteshpaul4093 Před 11 dny

      Still it will be a vector space because say x=-2 (-2,0,2) or or if x=2 then also(2,0,-2) both do belongs to S i.e (x,0,x)

  • @mehmettoktas5430
    @mehmettoktas5430 Před 3 lety +1

    Thanks for ur quality learning style Professor.Thanks from Turkey.

  • @simondx6694
    @simondx6694 Před 5 lety +39

    I already miss your long hair

  • @pwny4995
    @pwny4995 Před 2 lety +3

    What are the difference between a Span and a Subspace?

  • @Abdulrahman-hb6fy
    @Abdulrahman-hb6fy Před 4 měsíci

    the span of any number of elements of vector V is also a subspace of V
    a span is the smallest subspace of V that contains this set of elements
    span is important for describing vector spaces

  • @longvo2083
    @longvo2083 Před 2 lety +2

    Why the first question of the comprehensive is true? Could someone explain it please?

  • @user-uv3up3xe1r
    @user-uv3up3xe1r Před měsícem

    Thank you so much!

  • @mdmahmudhasan1645
    @mdmahmudhasan1645 Před 3 lety +1

    Clear explanation, carry on.

  • @user-yg6lf3ig2q
    @user-yg6lf3ig2q Před 2 lety

    You are really explaining brillians as we are always doing right in checking comprehension

  • @mrtoys3094
    @mrtoys3094 Před 3 lety

    Thank you for saving my semester professor much love from Kenyatta university ( Nairobi Kenya)

  • @nataliatothemoon
    @nataliatothemoon Před 3 lety

    Praying Tanaka is so lucky to have found you Professor Dave.

  • @navaerick86
    @navaerick86 Před 9 měsíci

    Wish I had a professor like you

  • @JJ-pz2dx
    @JJ-pz2dx Před 3 měsíci

    I have a midterm in 3 hours 😩 thank you so much

  • @ramankumar41
    @ramankumar41 Před rokem

    nice explanation Prof. Dave

  • @johnrhodes9964
    @johnrhodes9964 Před měsícem

    i have a doubt, the video tells that the definition of linear combination is "some of all the elements of a vector space multiplied by some scalars" and the definition of span is given as "set of all possible linear combinations". but in the example, only one possible linear combination of the vector space is considered and given the name span, shouldn't the span be a set of v1 v2 and v3 multiplied by diff series of scalars, why just stop with a b and c? x(v1) + y(v2) + z(v3) should also be a linear combination of the space. and the set of V multiplied by a,b,c and x,y,z should be called a span?

  • @honeycocoa1907
    @honeycocoa1907 Před 6 měsíci

    argh thank you so much i was having a hard time understanding all this. The video is so good i had to watch it 3 time lol

  • @thefrenchiestfry8147
    @thefrenchiestfry8147 Před 2 lety +2

    For closure under addition, do the vectors that are added to vectors in a subspace have to be part of the subspace themselves?

  • @k_nito7954
    @k_nito7954 Před 10 měsíci +3

    Hey sir! I was just wondering, can the scalar for the 1st rule of Vector Spaces be a negative? If yes, wouldn't it make the matrix in the 1st question of Checking Comprehension not a subspace? Since the -b in the bottom row would turn positive

    • @t.gmultiplex2838
      @t.gmultiplex2838 Před 7 měsíci

      I'm not a professor but if you are talking about the 2bd question in last then if 2nd row if b becomes positive then b in first row will to -b thus form will remain same

  • @quantumleap7964
    @quantumleap7964 Před rokem

    here is an interesting idea, since points in cartesian space are just sums of the i-hat and j-hat basis vectors with real coefficients technically speaking all of the 2-d coordinates system is simply span(i_hat,j_hat). Similarily the 3-d cartesian system is just span(i_hat,j_hat,k_hat)

  • @lankaputhra4825
    @lankaputhra4825 Před 2 měsíci

    What if sub space doesn’t include identity O but satisfies closure .
    It’s not a vector space is it? Still a subspace?
    If so not every subspace is vector space. Am I missing something ?

  • @yuboWang-be3cu
    @yuboWang-be3cu Před dnem

    what if one of a,b,c,d is a complex number???

  • @Smoothcurveup52
    @Smoothcurveup52 Před rokem

    Wow wonderful explaination

  • @sakinsayeem419
    @sakinsayeem419 Před rokem

    Can you please explain what you meant by 'Any sum of these elements" in 3:20

  • @abu-bakrmohamed1707
    @abu-bakrmohamed1707 Před 2 lety

    WOW , u made everything clear for me thank u so much :)

  • @kalpeshyadav1391
    @kalpeshyadav1391 Před 3 lety

    Awesone very nice explanation

  • @zxcxdr1
    @zxcxdr1 Před 2 lety

    English is my third language, and you still explain better than my professors in my mother tounge

  • @HWFieldGoal
    @HWFieldGoal Před 2 lety

    Thank you it is help full lecture!!!!

  • @joshuawang9401
    @joshuawang9401 Před 3 lety

    TY professor!

  • @curtpiazza1688
    @curtpiazza1688 Před 5 měsíci +1

    Great ! Thanx! 😂

  • @gamensmpro2819
    @gamensmpro2819 Před 2 lety

    Thanks

  • @dr.walidsoula
    @dr.walidsoula Před 2 lety

    Very nice,Thx

  • @nafiurrahman722
    @nafiurrahman722 Před 11 měsíci

    I didnt understand the part where span of V is the smallest subspace of V. How come? The a1V1+a2V2+a3V3 (if linearly independent) is the entire R3 right?

  • @karlmax61
    @karlmax61 Před 3 lety +1

    PLEASE MAKE LECTURES ON REAL ANALYSIS

  • @Sunny-qe5el
    @Sunny-qe5el Před 3 lety +1

    Multiplying zero scalar to a vector will yield zero result,
    So, in case of subspace, we could say that it is closed for scalar multiplication?

    • @Christian-mn8dh
      @Christian-mn8dh Před rokem

      c = 0 makes me think of another question. If c = 0, then the vector is [0,0,0]. which means it's not maintaining the [x,0,-x] form??? idk. pls help

  • @arefinsiddque6666
    @arefinsiddque6666 Před 2 lety +1

    Sir, multiply vector x with any negative constant value. Then, will the resultant vector x belong to the set S?

  • @Christian-mn8dh
    @Christian-mn8dh Před rokem +1

    2:20 is it really closed under scalar multiplication? what if c is negative???

    • @carultch
      @carultch Před rokem

      No issue if c is negative. The original vectors can be any vectors in the form of [[x],[0],[-x]], where x is any real number. The multiplier c, can also be any real number. Multiplying any two real numbers together, also gets a real number, and x*c will still be the negative of -x*c.

  • @nobody48803
    @nobody48803 Před 2 měsíci

    awesome

  • @alhadibalouch8442
    @alhadibalouch8442 Před 4 lety +1

    i have a midterm tomorrow thx

  • @kaanylmaz1008
    @kaanylmaz1008 Před 2 lety +1

    teşekkürler, iyi geldi

  • @qingyangzhang887
    @qingyangzhang887 Před 5 lety +3

    Thank you so much. By definition would a vector space be a (very useless) subspace of itself?

    • @AEPPLE_MUSIC
      @AEPPLE_MUSIC Před 2 lety +2

      Know it's too late but for anyone with a similar question: V is in itself a subspace of V.

    • @twi4458
      @twi4458 Před 2 lety

      @@AEPPLE_MUSIC Makes sense

    • @shriyanshkatiyar5807
      @shriyanshkatiyar5807 Před rokem

      YES OFCOURSE! IT WOULD BE. 🙂

  • @josephbadana5002
    @josephbadana5002 Před 4 lety

    thanK you so much.

  • @wenanyaugustine3311
    @wenanyaugustine3311 Před 11 měsíci +1

    what if you had used -1 as a scalar to multiply?

  • @kapjoteh
    @kapjoteh Před 3 lety +4

    2:28 what if c was -1

    • @bigilpandi7722
      @bigilpandi7722 Před 3 lety

      Scalar positive integer

    • @multitude1337
      @multitude1337 Před 2 lety +1

      @@bigilpandi7722 wrong

    • @multitude1337
      @multitude1337 Před 2 lety +3

      c can be any real number, remember it's a scalar, so it can be negative. thus, it will still work as the first component of the x vector has the opposite sign of the third component of the x vector, so it still satisfies this closure property

    • @Christian-mn8dh
      @Christian-mn8dh Před rokem

      @@multitude1337 so what does 'form' really mean? im confused

    • @carultch
      @carultch Před rokem

      @@Christian-mn8dh Think of form as meaning pattern. A vector in the form of [[x],[0],[-x]] means that you can put any (real in this case) number in the position of the x, in both the first and final entry of this vector. So this means that [[4], [0], [-4]] as well as [[-6], [0], [-6]] are vectors of this form. They have something in common, in that their first and final entries are negatives of each other, and they have zero for the middle entry.
      Note that the nested brackets is my way of indicating the vertical matrix, in an inline text description. Think of the innermost brackets as individual rows, and the outermost bracket as the full matrix of those rows. In this case, there's just one entry per row, since vectors in linear algebra are considered vertical matrices.

  • @suprememaster1951
    @suprememaster1951 Před 2 lety +1

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

  • @killercat50y
    @killercat50y Před 2 lety

    Don't know if you will ever see this comment, but thank you. You are getting me through my college linear algebra class. My teacher is so bad at explaining things, and you make it so simple to understand.

    • @ryanblanch2764
      @ryanblanch2764 Před rokem

      Same with my Linear Algebra Course. This is helping a lot.

  • @devendraonly239
    @devendraonly239 Před 7 měsíci

    2:00 why we are checking its closed or not, since its a subset of vector space..
    Confused!

    • @arvind9438
      @arvind9438 Před 4 měsíci

      we are trying to check if it is indeed a subset , thats why

  • @animeparadise2461
    @animeparadise2461 Před 11 měsíci

    Sir in Example of subspace what if we take the value of scalar as negative then the 1st property will not be held . Please help me with my doubt.

  • @hse2951
    @hse2951 Před 3 lety +1

    I don't understand R 2*2 Could you explained it

    • @johanjimenez1249
      @johanjimenez1249 Před 3 lety

      he made a video called understanding vector space

    • @carultch
      @carultch Před rokem

      The R refers to real numbers. The 2x2 refers to 2x2 square matrices. Putting it together, it refers to the set of all square matrices with 2 rows and 2 columns that contain any real number in each of the 4 entries.

  • @BagavaanSriKrishn
    @BagavaanSriKrishn Před 10 měsíci +3

    Watching 10 min before exam

  • @hero_of_winds7311
    @hero_of_winds7311 Před 5 měsíci

    Can someone explain #2 to me?

  • @bouyancyyang943
    @bouyancyyang943 Před 2 lety

    in 5:09 (2), can their span be in real number instead of a & b?

    • @amartyapanwar3164
      @amartyapanwar3164 Před rokem

      well, you assume a and b to be constants that are also real numbers. so the span, as a result, will be a real number, as you're not dealing with any variables here...hope this helps :)

  • @leoncraftmc
    @leoncraftmc Před 2 lety

    2:09, why is it “-(cx)”?
    c * (-x) is -cx

    • @ammyvl1
      @ammyvl1 Před 2 lety +1

      just to illustrate that it's some number in the form -x better

    • @carultch
      @carultch Před rokem

      Multiplication of real numbers is associative and commutative, so you can rearrange the parentheses and negative sign, however you prefer.

  • @Dilshannarankotuwa
    @Dilshannarankotuwa Před rokem

  • @syedannasali8039
    @syedannasali8039 Před rokem

    Hrs of lec

  • @rajanraju4194
    @rajanraju4194 Před 5 lety

    Private videos ??

  • @mcalkis5771
    @mcalkis5771 Před 2 lety

    Why the hell am I getting "Feet finder" ads on CZcams?? And on math tutorials of all places???

  • @vaibhavshilar7697
    @vaibhavshilar7697 Před 3 lety +1

    Sir Hindi

  • @justthenamekevin
    @justthenamekevin Před 2 lety

    french: Span is written as Vect

  • @hassannabil7309
    @hassannabil7309 Před 5 měsíci +2

    Midterm in 20 minutes 💀💀