Tensors Explained Intuitively: Covariant, Contravariant, Rank

Ғылым және технология

Tensors of rank 1, 2, and 3 visualized with covariant and contravariant components. My Patreon page is at / eugenek

Пікірлер: 1 200

  • @EugeneKhutoryansky
    @EugeneKhutoryansky4 жыл бұрын

    To see subtitles in other languages: Click on the gear symbol under the video, then click on "subtitles." Then select the language (You may need to scroll up and down to see all the languages available). --To change subtitle appearance: Scroll to the top of the language selection window and click "options." In the options window you can, for example, choose a different font color and background color, and set the "background opacity" to 100% to help make the subtitles more readable. --To turn the subtitles "on" or "off" altogether: Click the "CC" button under the video. --If you believe that the translation in the subtitles can be improved, please send me an email.

  • @dennercassio

    @dennercassio

    4 жыл бұрын

    It was a pleasure to translate this video to portuguese. Everyone should have the chance to learn a bit about tensor calculus.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    4 жыл бұрын

    Thanks. I appreciate the translation.

  • @no_one6749

    @no_one6749

    3 жыл бұрын

    What were these made with?

  • @adamhendry945

    @adamhendry945

    3 жыл бұрын

    @@no_one6749 This looks like OpenGL to me, or perhaps DirectX, probably programmed in C++.

  • @pauloneto7443

    @pauloneto7443

    2 жыл бұрын

    Eugene, can you tell me the name of the song, please?

  • @FredyeahEternal
    @FredyeahEternal7 жыл бұрын

    As a hobbyist mathematician you have no idea how valuable these videos are, please dont stop making them, you're helping people be smarter

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks. More videos are on their way.

  • @AkhilKumar-ci6pb

    @AkhilKumar-ci6pb

    5 жыл бұрын

    @@EugeneKhutoryansky how dot product gives vector

  • @tripp8833

    @tripp8833

    5 жыл бұрын

    @@AkhilKumar-ci6pb dot product doesn't give vector

  • @AkhilKumar-ci6pb

    @AkhilKumar-ci6pb

    5 жыл бұрын

    @@tripp8833 but in video it is daid like that what does it mean then at 2:40

  • @luismisanmartin98

    @luismisanmartin98

    5 жыл бұрын

    What it means is that we can get the components of the vector in a certain direction by doing the dot product of the vector with the basis vector in that direction. For example: V1(subscript 1, i.e. covariant component in direction 1)=V(vector)*e1(basis vector 1). [Where * is the dot product.]

  • @ianpool4330
    @ianpool43307 жыл бұрын

    I've spent so much time trying to find a simple explanation of covariant and contravariant vectors online, and in the first 3.5 minutes you've managed to out perform anything I've come across. A well deserved round of applause to you, Eugene! Keep up the great vids!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks.

  • @martinpetersson4350

    @martinpetersson4350

    7 жыл бұрын

    Eugene's videos are great but I still don't understand tensors :D

  • @martinpetersson4350

    @martinpetersson4350

    7 жыл бұрын

    Thanks I will!

  • @-danR

    @-danR

    7 жыл бұрын

    The title is misleading _almost_ to the point of clickbait. This video is an 'intuitive' explanation for those already familiar with tensors on a formal basis. It's a 'now I get it', or 'I never thought of tensors that way' for people who took tensor theory in university, etc. For a _genuine_ introduction for straight beginners, try Dan Fleisch' video. (I'm not Dan Fleisch, incidentally)

  • @good4usoul

    @good4usoul

    6 жыл бұрын

    I think this is the first time I ever saw a video where the person explaining had any idea why they were called covariant and contravariant. Other explanations I've seen have been as bad as "covariant means indices downstairs; contravariant means indices upstars." Which doesn't actually explain the meaning of covariant and contravariant at all, of course, but is a description of a notational convention.

  • @josh3658edwards
    @josh3658edwards7 жыл бұрын

    This channel is honestly top notch. Most resources are either too simplified to the point where they are not useful to someone who actually needs to learn this material, or they are so dense that a new learner gets lost in the details and misses the big picture. You do a great job at making the point clear (with the aid of amazing visuals) while also keeping everything accurate. Seriously, this is world class educational material. Get more famous!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks for the compliment.

  • @andrewk2625

    @andrewk2625

    2 жыл бұрын

    100% true

  • @black_wolf365
    @black_wolf3655 жыл бұрын

    The professors I had in the university while doing my Bachelors all failed to explain the concepts of covariant contravariant in an understandable manner. You have done what they have failed to do in less than 12 minutes! :D #RESPECT

  • @EugeneKhutoryansky
    @EugeneKhutoryansky5 жыл бұрын

    You can help translate this video by adding subtitles in other languages. To add a translation, click on the following link: kzread.info_video?v=CliW7kSxxWU&ref=share You will then be able to add translations for all the subtitles. You will also be able to provide a translation for the title of the video. Please remember to hit the submit button for both the title and for the subtitles, as they are submitted separately. Details about adding translations is available at support.google.com/youtube/answer/6054623?hl=en Thanks.

  • @leonardoramirezaparicio2060

    @leonardoramirezaparicio2060

    4 жыл бұрын

    What do you mean when you say that we can describe a vector in terms of its poin product with each of the base vectors?

  • @maurizioalfieri602

    @maurizioalfieri602

    4 жыл бұрын

    @Leonardo Ramìrez Aparicio. In my understanding, you can perform dot product and what you have are the componets of the vector IN ANOTHER BASIS, that is the dual basis.

  • @MsKhch

    @MsKhch

    3 жыл бұрын

    "Suppose we multiplay one of the contravariant component of the V with one of the contravariant component of the P" For what???

  • @MsKhch

    @MsKhch

    3 жыл бұрын

    "Suppose we multiplay one of the co-variant component of the V with one of the contravariant component of the P as shown" Why? And?

  • @MsKhch

    @MsKhch

    3 жыл бұрын

    7:50 WHAAAAT???????????? For what?

  • @amoghskulkarni
    @amoghskulkarni4 жыл бұрын

    Chronicles of tensors: the musical

  • @briseboy

    @briseboy

    3 жыл бұрын

    THe Wilhelm Tell Overture is hilarious as the proper covariant choice of music, you'll agree. A hidden dimension!

  • @EugeneKhutoryansky
    @EugeneKhutoryansky7 жыл бұрын

    If you like this video, you can help more people find it in their KZread search engine by clicking the like button, and writing a comment. Thanks.

  • @away5534

    @away5534

    7 жыл бұрын

    pin this comment so everyone can see

  • @gamwije7130

    @gamwije7130

    6 жыл бұрын

    Physics Videos by Eugene Khutoryansky

  • @kaustubhjoshi5559

    @kaustubhjoshi5559

    6 жыл бұрын

    Physics Videos by Eugene Khutoryansky

  • @josephli8837

    @josephli8837

    6 жыл бұрын

    The music is really, really, really distracting, classical music isn't really suitable as background music as its very structured, and often complex. Try using something more repetitive and 'boring'. 3blue1brown's way of doing it works very well.

  • @akashkalghatgi9352

    @akashkalghatgi9352

    6 жыл бұрын

    Next time, don't add such music

  • @umeng2002
    @umeng20026 жыл бұрын

    Having a good instructor makes a night and day difference when learning more advanced subjects. Great video. Making the jump from just dealing with vectors to tensors trips up a good number of people.

  • @kimweonill
    @kimweonill Жыл бұрын

    Your combination of graphics, content and music is otherworldly 😊

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    Жыл бұрын

    Thanks for the compliments.

  • @AndrewBrownK
    @AndrewBrownK6 жыл бұрын

    FINALLY A HELPFUL VISUAL REPRESENTATION!! I’ve been stuck on intuiting covariant vectors for YEARS! I think I get it now, it’s the *components* of the vector that are really covariant or contravariant, not the invariant/intrinsic vector itself

  • @MrRobertT03
    @MrRobertT037 жыл бұрын

    Eugene, your videos are absolutely incredible. Thank you for doing such a great job making things so well-explained and intuitive!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks.

  • @matt1285
    @matt12856 жыл бұрын

    The music when you got to rank 3 made me laugh

  • @JaySmith91
    @JaySmith917 жыл бұрын

    Excellent introduction to tensors. It's funny how you could complete a whole masters or PhD and never see these any more than a 2d drawing of these mathematical objects, but then a video comes along and in under 12 minutes shows you what it took so long to wrap your head around to imagine.

  • @JaySmith91

    @JaySmith91

    7 жыл бұрын

    Just some ideas. I wonder if it would be possible to visualise Lagrangian Mechanics, or Hamiltonian Mechanics. Or Calculus of Variations.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks. I will add those topics to my list of topics for future videos.

  • @MrTiti
    @MrTiti6 жыл бұрын

    our great classical music adds so much drama to on otherwise sober topic

  • @p72arroj
    @p72arroj4 жыл бұрын

    Really good video, you've done that people can visualize something which many professors didn't get in many years with their students and tried to explain as a teachers a visual concept with lots of usefuless words and few quality visualizations. Thanks

  • @gruminatorII
    @gruminatorII5 жыл бұрын

    Absolutely phenomenal video, i really wish we had these to study 8 years ago. I finally understood the difference between co and contravariant .... before i just knew the definition

  • @tiuk23
    @tiuk237 жыл бұрын

    Your channel should be promoted by some other famous channels, like Vsauce. Your videos are just too good. 3Blue1Brown got promoted this way. Maybe one day, this channel will as well.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks.

  • @WilliamDye-willdye

    @WilliamDye-willdye

    7 жыл бұрын

    tiuk23 : I think PBS Space Time would be a good candidate for collaboration.

  • @feynstein1004

    @feynstein1004

    7 жыл бұрын

    Duuude. I just promoted him on minutephysics.

  • @romanemul1

    @romanemul1

    6 жыл бұрын

    true

  • @gooshnpupp

    @gooshnpupp

    6 жыл бұрын

    totally agreed. what is missing here though, is the charisma of the speaker and aesthetic design, I guess, which makes alot of difference in this platform.

  • @pedromenezesribeiro7
    @pedromenezesribeiro76 жыл бұрын

    Finally someone could explain in a concise and clear manner what covariant and contravariant components are! Thanks a million!

  • @Steven-ro4of
    @Steven-ro4of4 жыл бұрын

    I've literally spent several years trying to understand tensors through self-studying to no avail. Your videos are the most intuitive and easy-to-understand way I've found and for the first time, I actually feel like I have a good understanding of tensors.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    4 жыл бұрын

    Glad my videos are helpful. Thanks.

  • @alexanderquilty5705
    @alexanderquilty57054 жыл бұрын

    The music makes this the most stress intense tensor video anime show I have ever seen in my life.

  • @beoptimistic5853

    @beoptimistic5853

    3 жыл бұрын

    kzread.info/dash/bejne/ioV9xNBrZ8e1mqg.html 💐💐

  • @probiner
    @probiner6 жыл бұрын

    I was looking into tensors 3 days ago and couldn't wrap my head around them and your video nailed it for me! Thanks a lot! Let me see if you have one on Quaternions, your skills might just finally break the wall for me to grasp how they are beyond Axis/Angle rotation and why if the axis is not normalized with a quaternion I get a skewed transform! Keep up!

  • @AzmeenfilmsIndia
    @AzmeenfilmsIndia6 жыл бұрын

    I thank you for your noble deeds and efforts put into creating these. This deserves as many shares as possible.

  • @samaraliwarsi
    @samaraliwarsi6 жыл бұрын

    I'm gonna wait for the next episode like I wait for the next episode of my favorite series. Great Job!!! Thank you so much for this :)

  • @zarchy55
    @zarchy557 жыл бұрын

    As always, the most excellent video!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Glad you liked my video.

  • @therealDannyVasquez
    @therealDannyVasquez7 жыл бұрын

    I didn't even know this was a thing! Amazing 😀

  • @Born2Losenot2win
    @Born2Losenot2win Жыл бұрын

    Omg, this channel is a Gold mine for upper division classes. Again thank you so much. You’re helping me with Quantum mechanics and Electrodynamics! Specially as a nonverbal visual learner this really helps!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    Жыл бұрын

    Thanks. I am glad my videos are helpful.

  • @rachelginsberg7890
    @rachelginsberg78905 жыл бұрын

    Thank you so much. I've been trying to get some sort of intuition for what a tensor is, and this is definitely the best video I've found to help me with that.

  • @DarkFunk1337
    @DarkFunk13377 жыл бұрын

    I wish you had uploaded this when I was taking Continuum Mechanics!

  • @jameshuang9568
    @jameshuang95685 жыл бұрын

    Thanks you for the exlanation. It helps me clear tons of mistaries! However, I am still a bit confused about the covariant component at 2:58. If the resultant vector remains constant and the base vectors are doubled in length, shouldn't the value of the components be decreased in order the result in the same vector? Please correct me if there's any misunderstanding.

  • @shadowlift1

    @shadowlift1

    4 жыл бұрын

    I also have this problem. To get the same vector, it seems you have to contra-vary in both cases, right?

  • @eliotnie

    @eliotnie

    2 жыл бұрын

    The dot product between two vector is given by the product of the normes times the cosinus between the 2 vectors : |v1| * |v2| * cos If |v1| stays constant and |v2| double in length then the dot product is doubled : it's covariant.

  • @lancelovecraft5913
    @lancelovecraft59137 жыл бұрын

    I have been waiting for this video since I first learned of tensors 2 years ago. Thank you

  • @pendalink
    @pendalink7 жыл бұрын

    Naturally, just as I start to learn about tensors, you release this. Thank youuuuuuu

  • @MrJesuswebes
    @MrJesuswebes6 жыл бұрын

    Just a humble piece of advice: I think music should be more "subtle". Orchestral music is beautiful but I think it can "bother" a little when you try to concentrate on explanations. Of course: this is my point of view, of course.

  • @RAFMnBgaming

    @RAFMnBgaming

    5 жыл бұрын

    Nah, this video could have done with a tad of Mars, Bringer of War if you ask me.

  • @cedricproper5256

    @cedricproper5256

    5 жыл бұрын

    @8:36 the music makes it worth waiting through a 5 minute ad to hear the punch line. It was great!

  • @JesusSoonComing

    @JesusSoonComing

    5 жыл бұрын

    Just a humble piece of advice: Use the mute button if you don't want to hear sound. I happen to enjoy the music...

  • @Gruuvin1

    @Gruuvin1

    5 жыл бұрын

    Yes, music level was distracting. And no, mute would not work, since the explanation is accomplished via audio (duh).

  • @JesusSoonComing

    @JesusSoonComing

    5 жыл бұрын

    "duh"?? That says it all...

  • @BarriosGroupie
    @BarriosGroupie3 жыл бұрын

    Great video. I prefer defining a covariant vector via its dot product with the corresponding contravariant vector being an invariant. This is how Tullio Levi-Civita defined it in his famous book, used by Einstein in his 1917 GR paper.

  • @jcave8580
    @jcave85804 жыл бұрын

    I am learning tensors by myself and this has been the most incredible explanation of covariant and contravariant components. Thanks for this work. It´s great!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    4 жыл бұрын

    Glad it was helpful. Thanks for the compliment.

  • @Insertnamesz
    @Insertnamesz7 жыл бұрын

    These videos are consistently enlightening. They should be part of curriculum. Well done!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks.

  • @descheleschilder401
    @descheleschilder4015 жыл бұрын

    Despite this being a great animation (like the one about Fourier transforms, which is even much better) this video I feel an inconsistency lurking with regard to the statement that the dot product decomposition is covariant. Let's take the most simple example of three orthogonal basis vectors and an arbitrary vector (like the situation around 20 seconds in this video). Now all the components of this vector are the dot product (orthogonal projections) with (on) the basis vectors. So if you make the basis vectors x times longer (or shorter) and giving this new basis vector the value 1 the components of the vector become x times as short (or long). But because the components are the dot product with the basis vectors, also the dot product decomposition becomes x-times as short, and this result is passed on to the case where the basis vectors are not orthogonal. Look for example at the video at around 2:58, where it is said that if you make the basis vector twice as large the dot product becomes twice as large too, but the basis vector you make twice as large gets again the value 1 and the corresponding vector component becomes twice as small (like is explained earlier: if you make the base vectors twice as large, the vector's components get twice as small), so each of dot product of the vector components with the basis vectors becomes x times smaller (larger) if you make the basis vectors x times larger (smaller), hence contravariance. A good example of a covariant vector follows from the (x,y,z) vector. This is a contravariant vector, but the (1/x,1/y,1/z) vector is a covariant one. More concrete, the wavelength vector [which corresponds to (x,y,z)] is a contravariant vector while the wavenumber vector, the number of waves per unit length, is a covariant vector [which corresponds to (1/x,1/y,1/z)]. See Wikipedia's "Contravariant and covariant" article.

  • @owenloh9300
    @owenloh93007 жыл бұрын

    Wtf i was trying to find the answer for this on the net and this just popped out in my notifications -crazy

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Glad I made this this video just in time for you. :)

  • @owenloh9300

    @owenloh9300

    7 жыл бұрын

    Physics Videos by Eugene Khutoryansky haha thx, always loved ur videos

  • @PremVijayVelMani

    @PremVijayVelMani

    7 жыл бұрын

    exactly rightly time for me too. whenever I have confusion in a particular topic, you are uploading a video in that topic exactly. Thank you very much.

  • @mikeandyholloway

    @mikeandyholloway

    5 жыл бұрын

    Google knows what you search. Google owns KZread. Makes sense

  • @edelcorrallira
    @edelcorrallira6 жыл бұрын

    Beautiful, such a great topic served with clarity and with great music in the background that was expertly timed. I love how the introduction of the covariant vector is joined by a very intense and vigorous passage that later resolves to calm once explained. Delightful !

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    6 жыл бұрын

    Glad you liked my video. Thanks.

  • @dabrownone
    @dabrownone6 жыл бұрын

    OMG, I can't believe I've been trying to figure out tensors, covariant/contravariant components, etc for so long, and it suddenly made complete sense. great work!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    6 жыл бұрын

    Glad to hear that my video was helpful. Thanks.

  • @PM-et6wz
    @PM-et6wz7 жыл бұрын

    You need to get your name out there. You should talk to other popular youtubers for support. Your videos are incredibly unique and informative, more people need to watch them. Professors should also be using your videos as to tool to teach students.

  • @TheAgentJesus
    @TheAgentJesus7 жыл бұрын

    THANK YOU SO MUCH, YOU ABSOLUTE SAGE AMONG MEN

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks for the compliment.

  • @TheAgentJesus

    @TheAgentJesus

    7 жыл бұрын

    Physics Videos by Eugene Khutoryansky in all seriousness, I have been searching for quite some time for a good intuitive demonstration of what a tensor actually IS, and what it "looks" like. I'm deeply grateful to you for at last providing a particularly helpful one - not that I'm at all surprised at the source, given your astounding track record for such things. Thank you once more, not only for this but for all of your different videos and the hard work that has clearly gone into them. They've helped me tremendously in my academic pursuits over the years, as I'm sure they've helped many others. You and others like you are an integral part of the future of modern education.

  • @mohammadmahmoody4657
    @mohammadmahmoody46576 жыл бұрын

    thanx alot you always focus on critical issues and help many people to understand in better way

  • @ericgarcia9769
    @ericgarcia97697 ай бұрын

    This is by far the best explanation about tensors that I could find. This has helped me tremendously for my general relativity class. Thank you so much!!!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 ай бұрын

    Thanks. I am glad my video was helpful.

  • @Jabber_Wock
    @Jabber_Wock7 жыл бұрын

    This is a great video, thanks Eugene and Kira! I understand your description of contravariant vectors, and how a vector can be represented by a contravariant combination of basis vectors. It would be great if you could elaborate on how a vector can be represented by a combination of dot products of arbitrary basis vectors. Perhaps "dot product" needs to be defined first (and "angle")?

  • @naixiancarucci242

    @naixiancarucci242

    2 жыл бұрын

    I was confused here: since dot product gives scalar but here it says the vector V can be represented by the dot products of basis vectors?

  • @malm7arb
    @malm7arb7 жыл бұрын

    I have never clicked on a notification this fast before.....

  • @feynstein1004

    @feynstein1004

    7 жыл бұрын

    Me neither

  • @plamenpetrov2014

    @plamenpetrov2014

    7 жыл бұрын

    Exactly!

  • @ishworshrestha3559

    @ishworshrestha3559

    4 жыл бұрын

    Ok

  • @tariq3erwa
    @tariq3erwa2 жыл бұрын

    Wow, the only video about tensors where I actually understand everything

  • @blakewilliams1478
    @blakewilliams14785 жыл бұрын

    Great video, first time I've ever gotten a straight answer about what a tensor is.

  • @qbslug
    @qbslug7 жыл бұрын

    so what is the difference between the 2nd rank tensors produced with covariant, contravarient and combination vectors?!?

  • @Whizzer

    @Whizzer

    6 жыл бұрын

    How they transform. A rank 2 tensor with two contravariant components transforms doubly contravariantly, which means the components get a lot smaller when the basis vectors get bigger. A rank 2 tensor with two covariant component gets a lot bigger when the vectors get bigger.

  • @TheKyshu

    @TheKyshu

    6 жыл бұрын

    Whizzer191: Do you know an example for a field/application where the version with two contravariant components would be used instead of the other example? I can't think of a way where I'd use it over the other one.

  • @delawarepilot
    @delawarepilot7 жыл бұрын

    Great videos. I can't wait to see the one on Einstein's field equation

  • @TheLonelyTraveler142
    @TheLonelyTraveler1427 жыл бұрын

    I've been looking for so long for a nice explanation of what a tensor is. You really are the best at explaining physics and math, thank you.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks for the compliment.

  • @dixshants1227
    @dixshants12273 жыл бұрын

    This is amazing. I am so appreciative of all the work you have put into these animations!! Unbelievable stuff

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    3 жыл бұрын

    Thanks for the compliments.

  • @fawbri2654
    @fawbri26546 жыл бұрын

    Hi,Thanks for the video and the explanations.In the beginning of the video you say "if we double the length of the basis vectors, the dot product doubles" if V = (2, 0) in the basis e1 = (1, 0), e2 = (0, 1), V.e1 = 2 But if e1' = (2, 0), V in the new basis would be V = (1, 0), and V.e1' = 2 So why didn't you express V in the new basis for the dot product but you did it for the normal components of V ?

  • @rudolfgelpke3258

    @rudolfgelpke3258

    6 жыл бұрын

    (First I thought "what a sensible explanation" ... then I realized I don't get the covariant case, having the impression it played out similar to the contravariant case ... but days later ...) (As of now, edited, my comment doesn't fit here as a comment on Faw Bri) I believe I understand now. Before, I was wrong in two points: 1) I did not fully understand the dot product. It goes like (V dot E = |V| |Ê| cos(angle V-Ê)). Having learned the dot product in the context of coordinate systems with orthonormal basis vectors (all basis vectors at right angle to each other and of UNIT length), I IGNORED the basis vector's magnitude as a factor (it used to be always 1, because of unit basis vectors). 2) Even though explicitly stated in the video, I still did not realize that the the new component equals in fact the dot product itself. Instead, I wrongly assumed the new component to be that multiple of the basis vector length that is equal in lenght to the projection of vector V onto that basis vector Ê (alike to the contravariant case, where the component is a multiple of the pertaining basis vector).

  • @asterisqueetperil2149
    @asterisqueetperil21496 жыл бұрын

    I am a bit confused by your statement about the covariant components. If you double the length of your basis vector, the scalar product with the basis vector (so your covariant components) will be divided by 2 and not multiplied ? Or if you don't set the new length as the new unit but just multiply by 2, then the scalar product remain the same ? In my understanding of tensors, the contravariant basis (ie the covariant components) was defined by the invariance of the covariant-contravariant product, that is by the metric tensor. May you clarify this point for me please ? And keep up the good work !

  • @emanuelaene862

    @emanuelaene862

    5 жыл бұрын

    Asterisque and others, I'm trying to clarify this for you. Let's take the magnitude of v-vector sqrt(136). This magnitude comes from a rectangular "box" with the sides 6, 6, and 8. This "chosen" vector makes the angles 1,2,3 with the three directions of the basis vectors e1, e2, and e3. If the length of all vectors in the basis is 1, then (v)dot(e1)=sqrt(136)*cos(angle1), (v)dot(e2)=sqrt(136)*cos(angle2), and (v)dot(e3)=sqrt(136)*cos(angle3). Now, let's increase the length of all vectors in the basis to 2. The new dot products will be: (v)dot(e1new)=2*sqrt(136)*cos(angle1), etc. The values of these "new" dots product are the doubles of the "old" ones because the angles do not change. The dot products are covariant. In the "old" basis, the contravariant components of the v-vector were (6,6,8) while in the "new" basis they will be (3,3,4). The length of the contravariant components decreases when the magnitudes of the vector-basis increases.

  • @emanuelaene862

    @emanuelaene862

    5 жыл бұрын

    The tensor made by multiplying the contravariant components to the dot products stays invariant, of course.

  • @prenomnom5057
    @prenomnom50576 жыл бұрын

    Simply EXCELLENT. I never post comments on KZread but this deserves to be the TOP video in any search on the topic.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    6 жыл бұрын

    Thanks. I am glad you liked my video.

  • @rachelginsberg7890
    @rachelginsberg78905 жыл бұрын

    Also, I liked the music :) It matched the excitement I felt at finally understanding this!

  • @xgozulx
    @xgozulx6 жыл бұрын

    Your videos are so awesome. Note. I've never used super index values as you showed, I alwais use sub indexes

  • @Intrebute
    @Intrebute7 жыл бұрын

    In the video you mention that the same rank 2 tensor composed of two vectors can be described as various combinations of covariant and contravariant components of those two vectors. My question is, are these different representations completely determined by each other? For example, if you have a rank 2 tensor T, which you know was composed by the covariant components of a vector P and the contravariant components of a vector V, can you tell what the representation would be if you wanted it to be composed of the _contravariant_ components of P and the _covariant_ components of V, instead? Even if you don't know the actual vectors P and V but only the tensor T? Another question is, all these representations composed from different combinations of "variances" of some component vectors P and V feel like they would all be 'nicely' related to each other. Kind of how different basis vectors give different different representations of the same vector. Do all these combinations form a nice structure, similar to how vectors are still vectors despite the choice of basis used to represent them, if any?

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    If you know the metric for the space, then you can determine the covariant components from the contravariant components, or the contravariant components from the covariant components. The metric for the space is defined by the metric tensor, which lets us know how to calculate the length of a vector, given the vector's covariant or contravariant components. I plan to cover the metric tensor in my next video.

  • @yizhang7027
    @yizhang70273 жыл бұрын

    After days of research, I can finally appreciate this video. Thank you very much for making it.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    3 жыл бұрын

    Thanks.

  • @Physicsnerd1
    @Physicsnerd16 жыл бұрын

    Excellent Eugene. Great explanation and visual of co-variant, contra-variant, and sub/super scripts. Nice to grasp the concepts and rules of the game. I have had two different physics instructors who couldn't explain what you have put so succinctly. I have also read many texts that convoluted such simple material. I look forward to watching more of your videos. Thank you so very much!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    6 жыл бұрын

    Thanks. I am glad you liked my video and I hope you enjoy my other videos too.

  • @muzammalsafdar1
    @muzammalsafdar17 жыл бұрын

    best explained

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    Thanks.

  • @MuggsMcGinnis
    @MuggsMcGinnis6 жыл бұрын

    The contra-variant components are shown graphically to be related to the vector's length but the co-variant components are not. It doesn't show how one could derive the vector from the co-variant basis vectors which can apparently be multiplied to any size without changing the vector they define. When the covariant components were increased or decreased, the vector was unchanged.

  • @Titurel

    @Titurel

    3 жыл бұрын

    @planet42 THanks for clearing that up

  • @quantumworld9434
    @quantumworld94342 жыл бұрын

    Great video. Now I got a clear concept about tensor. This is the best video in KZread to get a visualization of tensor physically.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    2 жыл бұрын

    Thanks for the compliment. I am glad my video was helpful.

  • @kevinbyrne4538
    @kevinbyrne45385 жыл бұрын

    For DECADES I've searched for an explanation of tensors that's as simple as the one that you've presented here in less than 12 minutes. Thank you, thank you, thank you ! I am in your debt.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    5 жыл бұрын

    Glad my video was helpful. Thanks.

  • @SupremeCommander0
    @SupremeCommander07 жыл бұрын

    what is geometrically a dot product of two vectors ab? aside of the area |a|cosf x |b|cosf, what does it mean?

  • @SupremeCommander0

    @SupremeCommander0

    7 жыл бұрын

    if we have two vectors a and b, I just can't get what is dot product from this perspective

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    I cover dot products in my video at kzread.info/dash/bejne/mmSCrK1tnaiverg.html

  • @lisalisa9706

    @lisalisa9706

    7 жыл бұрын

    You can think of a dot b as being the length of the projection of vector a in the direction of b "stretched" |b| times. Or the length of the projection of b in the direction of a multiplied by |a|, it will give the same answer. In physics this can be thought of as the work of a along the displacement b, in maths it is simply vector projection, or as you said, an area.

  • @SupremeCommander0

    @SupremeCommander0

    7 жыл бұрын

    Thank you!

  • @h2ogun26
    @h2ogun267 жыл бұрын

    covariant vector.. im little confused when the value of dot products doubles along the doubling of basis' length, isnt the vector( white one. or V vector as you wrote) should expressed in basis which is before doubled? notice me if what my comment is imperceptible.

  • @h2ogun26

    @h2ogun26

    7 жыл бұрын

    also i'd like to know the intuition of using del operator as covariant vector.

  • @fawbri2654

    @fawbri2654

    6 жыл бұрын

    Agree! Was not convinced by this point

  • @abhayshankar8762

    @abhayshankar8762

    4 жыл бұрын

    You’ve got it the other way around, the vector always stays the same, that is a given; it is independent of the basis. When we change the basis vectors keeping the white one constant, it’s dot product changes in the same direction. Like, 1 kg and 1000g are the same mass, but are expressed differently here.

  • @Endever42

    @Endever42

    3 жыл бұрын

    @@h2ogun26 check out this series: kzread.info/head/PLRlVmXqzHjUQARA37r4Qw3SHPqVXgqO6c or if you really want to know, why the del is used: kzread.info/head/PLRlVmXqzHjUQHEx63ZFxV-0Ortgf-rpJo

  • @shwetasharma5848
    @shwetasharma58484 жыл бұрын

    Thankyou! Now I can see the imagination of those great personalities who discovered these concepts

  • @beoptimistic5853

    @beoptimistic5853

    3 жыл бұрын

    kzread.info/dash/bejne/ioV9xNBrZ8e1mqg.html 💐💐

  • @yamansanghavi
    @yamansanghavi6 жыл бұрын

    This channel should be a standard thing to be studied in colleges and universities.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    6 жыл бұрын

    Thanks.

  • @cliffpetersen6881
    @cliffpetersen68814 жыл бұрын

    Thank you for the clarity - the music does get in the way however, would you consider making it much softer or not having it at all?

  • @beoptimistic5853

    @beoptimistic5853

    3 жыл бұрын

    kzread.info/dash/bejne/ioV9xNBrZ8e1mqg.html 💐

  • @dzanc
    @dzanc5 жыл бұрын

    Explenation of rank 3 tensor *William Tell overture ensues* ayy lmao

  • @fernandoescobar4039
    @fernandoescobar40395 жыл бұрын

    Thank you for your service..! It is great help to understand these topics.

  • @josephmazor725
    @josephmazor7252 жыл бұрын

    Thank you for the description of tensors, it’s one of the most intuitive I’ve seen

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    2 жыл бұрын

    Thanks. I am glad you liked my video.

  • @francissanguyo2813
    @francissanguyo28137 жыл бұрын

    Hmm... I would like to see a video regarding the Navier-Stokes Equations... somewhere in the future.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    I will add the Navier-Stokes Equations to my list of topics for future videos. Thanks.

  • @francissanguyo2813

    @francissanguyo2813

    7 жыл бұрын

    No problem, and thanks.

  • @zbzb-ic1sr

    @zbzb-ic1sr

    6 жыл бұрын

    That would be something to look forward to *excited*

  • @MrPetoria33
    @MrPetoria336 жыл бұрын

    I highly recommend the videos by Prof. Pavel Grinfeld (MathTheBeautiful) for more on this subject, as well as his textbook, which focuses on geometrically intuitive approaches to this subject. Prof. Bernard Schutz's books are also excellent, though they require more mathematical maturity on the part of the reader.

  • @harleyspeedthrust4013

    @harleyspeedthrust4013

    2 жыл бұрын

    I second Prof. Grinfeld's series of lectures. They are fantastic, and he explains the subject very carefully and well.

  • @timharris72
    @timharris726 жыл бұрын

    This is the best explanation of tensors I have seen so far. Thanks for posting.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    6 жыл бұрын

    Thanks for the compliment about my explanation.

  • @mermaid6380
    @mermaid63805 жыл бұрын

    I like it a lot for the "slow" speed. It made the concept more understandable. Thanks!

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    5 жыл бұрын

    Thanks.

  • @ivanbykov7649
    @ivanbykov76496 жыл бұрын

    the music is epic

  • @ivana4638

    @ivana4638

    4 жыл бұрын

    Agreed

  • @atimholt

    @atimholt

    3 жыл бұрын

    The William Tell Overture. I grew up with a classical music compilation CD (one of those various “Greatest Hits of the Classics” compilations). Though I *first* encountered the first two movements in old cartoons (there used to be a lot more classical music in cartoons), and had occasionally heard bits of the last movement in the context of The Lone Ranger.

  • @nogmeerjan
    @nogmeerjan7 жыл бұрын

    I seem to miss the dot product knowledge to understand the story :-( Maybe a good idea for a future video?

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    I cover dot products in my video at kzread.info/dash/bejne/mmSCrK1tnaiverg.html

  • @nogmeerjan

    @nogmeerjan

    7 жыл бұрын

    Thanks. I looked for it and failed to find it.

  • @dmitry8038

    @dmitry8038

    7 жыл бұрын

    может стоит сделать сайт с нормальной навигацией по темам?

  • @varun3101
    @varun31015 жыл бұрын

    this is most beautiful video i ever found on youtube.. huge respect for the team who made it

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    5 жыл бұрын

    Thanks for the compliment.

  • @ian-haggerty
    @ian-haggerty6 жыл бұрын

    Yessss! Finally an explanation behind the terminology "covariant" and "contravariant". It's alien language like this that can really throw me off learning new topics in physics & math. MAHASIVE Props to you.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    6 жыл бұрын

    Thanks.

  • @banshee511
    @banshee5116 жыл бұрын

    I love the video! However, the music is too good. It is really distracting.

  • @tempestaspraefert
    @tempestaspraefert6 жыл бұрын

    Information density is a bit low, even when on 2x speed. The constant movement of the "3d objects" is a bit unnecessary. I still hit that like button, because the matter discussed is quite abstract and the explanation splendid! Well done ;-)

  • @wolfman83778

    @wolfman83778

    5 жыл бұрын

    It's done that way to let you absorb what they're saying.

  • @paulbaker916
    @paulbaker9166 жыл бұрын

    So good to see you back. Superb as always.

  • @Jacob011
    @Jacob0115 жыл бұрын

    This is awesome! I FINALLY understand all that co-variant and contra-variant business. I've never seen it explained so well.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    5 жыл бұрын

    Thanks.

  • @palpytine
    @palpytine5 жыл бұрын

    Suppose we just shove some numbers together in some particular order. Not going to say *why*, but hey... at least they're swaying constantly. Suppose we then claim this to be intuitive.

  • @abhayshankar8762

    @abhayshankar8762

    4 жыл бұрын

    Suppose we get a life, eh?

  • @blackriver2531
    @blackriver25316 жыл бұрын

    51 people accidentally clicked dislike.

  • @xrisku

    @xrisku

    6 жыл бұрын

    Lily Winters it's probably due to the obnoxious music. the visuals are great, but the music is too loud and distracting.

  • @ramsharma9568

    @ramsharma9568

    6 жыл бұрын

    I don't know why the mistake is increasing.

  • @ArpanD
    @ArpanD4 жыл бұрын

    Forever changed the way i look at maths. THANKS AWFULLY EUGENE. U R DOING A MILLION DOLLAR JOB ACTUALLY U DESERVE BETTER. GO AHEAD SIR

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    4 жыл бұрын

    Thanks for the compliment and I am glad that my videos have been helpful. Thanks.

  • @winniephy6
    @winniephy65 жыл бұрын

    Wonderful....! Just amazing.... Eugene... Your videos definitely make life easier for those who truely want to master physics and mathematical concepts.... Kudos for you efforts and pranams for the profound Knowledge that you are imparting through ur videos.!

  • @Ricky-zc8qm
    @Ricky-zc8qm6 жыл бұрын

    V and P for the Tensors, Yes yes, I can sense their relationship, subliminally they will become one.

  • @david21686
    @david216867 жыл бұрын

    Really? Einstein's field equations in the next video? You're going to skip over raising and lowering indices (which I really wanted to see), special relativity, curvature, the Riemann tensor, the stress energy tensor, and go straight into Einstein's field equation?

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    7 жыл бұрын

    I already covered both Special and General Relativity in many of my earlier videos. I plan to cover raising and lowering indices, curvature, the Reimann tensor, and the stress energy tensor all in my next video. Thanks.

  • @psient

    @psient

    6 жыл бұрын

    Uses people as a means to an end. Not very reality based, in the Buberesque use of the word ethics..

  • @myrtoh.964

    @myrtoh.964

    6 жыл бұрын

    you're really rude bro

  • @ConceptsMadeEasyByAli
    @ConceptsMadeEasyByAli6 жыл бұрын

    This is so much better description and intuitive. God bless.

  • @TheGamshid
    @TheGamshid6 жыл бұрын

    you are the best, Please don't stop. You are really making a difference.

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    6 жыл бұрын

    Thanks. More videos are on their way.

  • @user-ib8sy4qu8l
    @user-ib8sy4qu8l6 жыл бұрын

    The bleeding obvious, repeated over and over, under nut-cracking classical miuzak!

  • @CasperBHansen
    @CasperBHansen5 ай бұрын

    Very distracting music 😅

  • @ClawHammermusic
    @ClawHammermusic6 жыл бұрын

    Such a tease! Can't wait for your intuition on the "Field Equations."

  • @maurocruz1824
    @maurocruz18246 жыл бұрын

    I simply can't understand why this topic in the books is so entangled and you just made up so easy!

  • @ba_livernes
    @ba_livernes6 жыл бұрын

    Please, I beg you to stop moving things around so much when not necessary. It makes the video very hard to follow.

  • @kostaflex1994
    @kostaflex19942 жыл бұрын

    the music is distracting

  • @bobbywasabi4082
    @bobbywasabi40827 жыл бұрын

    Thank you so much for doing the field equations I always wanted to learn about it!

  • @srushtisonavane
    @srushtisonavane5 жыл бұрын

    Excellent explanation to Tensors, your animation is on completely different level n so is your explanation. This video really helped me to clear my all doubts regarding tensors. I simply loved it. Thank you so much :)

  • @EugeneKhutoryansky

    @EugeneKhutoryansky

    5 жыл бұрын

    Thanks for the compliment about my video.

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