What is Jacobian? | The right way of thinking derivatives and integrals

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  • Опубликовано: 3 июн 2024
  • Jacobian matrix and determinant are very important in multivariable calculus, but to understand them, we first need to rethink what derivatives and integrals mean. We can't think of derivatives as slopes if you want to generalise - there are four dimensions to graph the function! This video hopes to explain what the Jacobian matrix and determinant really mean, and essentially why they are actually very natural for changing variables; and also explaining something that might be glossed over when you use them - for example, we require absolute value, and the changing variables function is injective.
    In the video, we have only talked about 2D transformations, but the Jacobian can be easily generalised to any number of dimensions you like - you just need to introduce linear maps in higher dimensions! Think about what that means in 3 dimensions for a start!
    This video simply aims to introduce the intuition of the Jacobian, and so a lot of things said in the video is not going to be very rigorous - for example, what does approximate mean? It has a specific meaning in mathematics, but we are not getting there; and also not all functions have this nice property of looking like a linear map near a point. These belong to the realm of real analysis, which is well beyond the scope of this video. So please don't shout Fubini's theorem when you see flipping the order of integration at about 17:09.
    Video chapter feature:
    00:00 Introduction
    01:20 Chapter 1: Linear maps
    06:01 Chapter 2: Derivatives in 1D
    08:08 Chapter 3: Derivatives in 2D
    13:01 Chapter 4: What is integration?
    17:26 Chapter 5: Changing variables in integration (1D)
    19:25 Chapter 6: Changing variables in integration (2D)
    22:59 Chapter 7: Cartesian to polar
    If you are interested in thinking about how the formula for the determinant came about, here is it: moodle.tau.ac.il/2018/pluginf... (p. 134, 135)
    Other than commenting on the video, you are very welcome to fill in a Google form linked below, which helps me make better videos by catering for your math levels:
    forms.gle/QJ29hocF9uQAyZyH6
    If you want to know more interesting Mathematics, stay tuned for the next video!
    SUBSCRIBE and see you in the next video!
    If you are wondering how I made all these videos, even though it is stylistically similar to 3Blue1Brown, I don't use his animation engine Manim, but I will probably reveal how I did it in a potential subscriber milestone, so do subscribe!
    Social media:
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    For my contact email, check my About page on a PC.
    See you next time!

Комментарии • 1,2 тыс.

  • @mathemaniac
    @mathemaniac  3 года назад +670

    This video took a huge amount of time and effort to produce, so if you want to and can afford to, support this channel on Patreon: www.patreon.com/mathemaniac
    The Google form is also linked here so that you don't have to read the description: forms.gle/QJ29hocF9uQAyZyH6
    The next video will finally tackle the problem of average distance between two points in a unit disc analytically - no more simulations. I am quite proud of this video, and took almost certainly more time (I didn't keep track this time) than any other video on this channel, even though it might not perform as well in the RUclips algorithm, but whatever, I like what I made here :)
    Do leave a like, subscribe and leave a comment now, so that more people can watch this!

    • @colorfulquesadilla377
      @colorfulquesadilla377 3 года назад +9

      I can’t wait to see it! :D

    • @mathemaniac
      @mathemaniac  3 года назад +6

      @@colorfulquesadilla377 Thanks for the support! I can't wait for the video to drop as well!

    • @ranam
      @ranam 3 года назад +1

      If Jacobian is an cure to exploding convergence by finding the correct scaling factor using determinant and we use it for symbolic calculation but why do we use Jacobian based element in finite element analysis since that is also an integral why is Jacobian used in both numerical and symbolic calculation s

    • @ranam
      @ranam 3 года назад

      If Jacobian is an cure to exploding convergence by finding the correct scaling factor using determinant and we use it for symbolic calculation but why do we use Jacobian based element in finite element analysis since that is also an integral why is Jacobian used in both numerical and symbolic calculation s

    • @vishnuts8385
      @vishnuts8385 3 года назад +3

      This is really helpful...thanks alot

  • @NonTwinBrothers
    @NonTwinBrothers 3 года назад +4139

    I love how RUclips is now exploding with math channels

    • @mathemaniac
      @mathemaniac  3 года назад +343

      which is good :)

    • @joshuascholar3220
      @joshuascholar3220 2 года назад +59

      I found a physics crank channel today, I wonder if there are math crank channels.

    • @Julle399
      @Julle399 2 года назад +11

      What are some other good ones bro?

    • @nikilragav
      @nikilragav 2 года назад +19

      @@joshuascholar3220 what does this mean? Someone who teaches things incorrectly as a prank?

    • @joshuascholar3220
      @joshuascholar3220 2 года назад +56

      @@nikilragav not as a prank, but because they were incapable of learning correctly, came up with their own theories and who, out of injured pride scream that everyone who isn't a crank is a fraud.
      That's about the shape of the average crank. Some of them were capable of being educated and don't hate everyone - but do have grudges against some famous people and their work. Generally those people have an extreme lack of ability to put things in context like most nuts.

  • @adamdapatsfan
    @adamdapatsfan Год назад +559

    Came for the Jacobian, stayed because - almost by accident - _you gave an intuitive explanation of the chain rule!_

    • @mathemaniac
      @mathemaniac  Год назад +83

      That was the whole reason I am making this video, because many people have talked about Jacobian before, and this explanation of integration by changing variables was hopefully something "new" on RUclips.

    • @hariam9574
      @hariam9574 4 месяца назад

      Same here

  • @NuclearSpinach
    @NuclearSpinach 2 года назад +155

    I have BS/MS in math, MS in statistics, and next year I'm finishing a statistics PhD, and I've never seen vector calc presented this way. Thank you for the illumination.

    • @user-gs1lz2pw9v
      @user-gs1lz2pw9v 8 месяцев назад +9

      Your name makes me imagine a cartoon about Popeye getting radioactive powers

    • @NuclearSpinach
      @NuclearSpinach 8 месяцев назад

      @@user-gs1lz2pw9v I think my then-14-year-old-self was thinking along those lines :)

    • @ohgosh5892
      @ohgosh5892 5 месяцев назад +3

      Look at 3 blue two brown. A whole new level of animation of transformations.

    • @ohgosh5892
      @ohgosh5892 5 месяцев назад +1

      1 blue 3 brown? 5 brown 6 blue? One of those!

    • @user-gs1lz2pw9v
      @user-gs1lz2pw9v 5 месяцев назад

      @@ohgosh5892 you fucks with sacred heart geometry

  • @robertlinder6414
    @robertlinder6414 2 года назад +593

    After 40 years of college, finally a good explanation .

    • @sorvex9
      @sorvex9 Год назад +48

      Sorry what, 40 years of College ?

    • @TheBambooooooooo
      @TheBambooooooooo Год назад +65

      @@sorvex9 oh you can't be this pedantic, he obviously meant 40 years after passing his college. God damm

    • @tbg-brawlstars
      @tbg-brawlstars Год назад +5

      @@sorvex9 🤣🤣🤣🤣

    • @franckherrmannsen7903
      @franckherrmannsen7903 Год назад +3

      haha my first thought🙃 as i got to the explanation of the matrix via warped linear coordinates

    • @davideskerlot2945
      @davideskerlot2945 Год назад +2

      Ah yes, the King of getting left back.

  • @leobieker9631
    @leobieker9631 3 года назад +854

    This managed to make more of an impression on me than my entire university linear algebra class. Most professors seem to just read off a PowerPoint.

    • @mathemaniac
      @mathemaniac  3 года назад +56

      Thanks so much for the appreciation!

    • @Assault_Butter_Knife
      @Assault_Butter_Knife 3 года назад +40

      Exactly, I end up studying most of the course content on my own. Thankfully there's great content like this that I can use in my studies

    • @satyakisil9711
      @satyakisil9711 3 года назад +14

      I can confirm that they do just that.

    • @johnwilson8309
      @johnwilson8309 3 года назад +9

      I hate powerpoints and pretty much refused to teach from them

    • @midnightwatchman1
      @midnightwatchman1 3 года назад +13

      @@johnwilson8309 do not blame the tool blame the craftsman. I love them, I like teaching from them and allows me to modify by work in real-time. sometimes someone asks an interesting question and I just markup it up right there. afterward, i decide whether it a hidden slide or something incorporated in the main class

  • @brianhowell7626
    @brianhowell7626 3 года назад +208

    back in 2018 i spent some time learning how code animations using manim and realized how much work it requires. i became sad once i realized there was no way 3b1b was ever going to come close to animating all of maths. now i am very excited to see all of these channels coming out and tackling these concepts! thank you for your contribution to humanity

    • @mathemaniac
      @mathemaniac  3 года назад +29

      It does take a lot of work! But actually, I don't use Manim :)

    • @andrewmole3355
      @andrewmole3355 2 года назад +7

      As a matter of interest, what do you use? Manim is fairly good,. I have been looking at Blender for more complex animations.
      PS. Great presentation - I have always been afraid of Jacobians because I didn’t understand why they existed.

    • @yaqubroli1804
      @yaqubroli1804 Год назад +4

      @@andrewmole3355 He makes animations using a combination of Powerpoint and Geogebra; there's a video about it somewhere on his channel, I think.

    • @Godfather-qr6ej
      @Godfather-qr6ej 2 месяца назад

      @@mathemaniac you have provided more to the world than the likes of Elon

  • @RedStinger_0
    @RedStinger_0 3 года назад +805

    I have yet to learn multivariable calculus and area integrals, and this seems to make things a bit more digestible for me. Neat video, man!

    • @mathemaniac
      @mathemaniac  3 года назад +34

      Glad it helps!

    • @zyansheep
      @zyansheep 3 года назад +12

      @@mathemaniac absolutely. I never knew to think of 2d matrices as scaling the up and right vector

    • @adjoint_functor
      @adjoint_functor 2 года назад +15

      @@zyansheep If you’re still struggling with matrix intuition, I’d reccomend 3blue1brown’s seties on linear algebra.

    • @orang1921
      @orang1921 6 месяцев назад

      Area integrals? What other type would you have learned before that?

    • @CoolBro-yf6of
      @CoolBro-yf6of 27 дней назад

      @@orang1921 line integrals duh...

  • @martinjohnsons4523
    @martinjohnsons4523 3 года назад +585

    vsauce narrative + 3blue1brown animation

    • @organiccaveman
      @organiccaveman 3 года назад +19

      after the iconic music I expect " Hey vsauce !......Michael here"

    • @darkenviado3446
      @darkenviado3446 3 года назад +4

      I was just going to write this exact comment 🤣

    • @Cl0udEater
      @Cl0udEater 3 года назад

      Yeah, same thought here. Good times

    • @darrellee8194
      @darrellee8194 3 года назад +3

      @@Cl0udEater Makes me appreciate Soothing Grant’s voice is

    • @TheZenytram
      @TheZenytram 2 года назад +1

      - the clarity of both

  • @ASASID2
    @ASASID2 3 года назад +286

    I'm in last year of my Mathematics degree, and I feel I just started understanding determinants and Jacobians right now!!
    Thanks a lot

  • @gonzalezm244
    @gonzalezm244 3 года назад +200

    I started learning calculus 7 years ago, and I’m still learning new perspectives of derivatives and integrals today. It’s such a fascinating subject. I actually had this intuition for 2d+ cases, but applying it back to 1d cases was what really made it click just now haha. This is very helpful for those of us who had trouble connecting u-substitution to using the Jacobians to change variables. It’s the same exact thing!
    Please do one for vector calculus 🙏

    • @mathemaniac
      @mathemaniac  3 года назад +8

      Thanks for the appreciation! Glad that it helps.
      I am not sure which part of vector calculus you are talking about though, but I will probably consider it.

    • @canriecrystol
      @canriecrystol 3 года назад +6

      @@mathemaniac I think he's talking about line and surface integrals. Maybe that's not what he's refering to, but what I'd like to see. I've been studying integration of differential forms, and parameterization kinda confuses me, eg., integrating a 2 form over a sphere. How does matching each coordinate plane (dx^dy, dy^dz.dz^dx) to the coordinate plane given by the parameterization (dφ^dθ) work? It's not a one to one thing like what happens to integrals over intervals.

    • @gonzalezm244
      @gonzalezm244 3 года назад +6

      @@canriecrystol yes, this is it. More specifically, the General Stokes’ Theorem

  • @NextazxzNoExuse
    @NextazxzNoExuse 2 года назад +33

    with a heavy heart I clicked this, having a physics degree and never knowing why we were even learning jacobians back in the day. Thanks lol

    • @ChristAliveForevermore
      @ChristAliveForevermore 2 года назад +2

      I'm in the exact same boat. Jacobians, Hermitian Operators, Hilbert Space, they all came at us so fast I didn't even have time to process them. I just went about computing what I could for a grade because that's all you can do sometimes when in University.

  • @Boringpenguin
    @Boringpenguin 2 года назад +15

    This is the only time I truly understand the Jacobian geometrically, I wish I could've bumped into this video sooner. Great stuff!

  • @Aio-Project
    @Aio-Project 3 года назад +139

    awesome intuitions on change of base in the context of calculus. I can see the 3b1b influence all over this content and i love that too

    • @mathemaniac
      @mathemaniac  3 года назад +20

      Thanks so much for the appreciation!

    • @yednekachewgeremew1886
      @yednekachewgeremew1886 2 года назад +1

      when x explain intuitions on the base of cordinate they are indicating motives and character i.e derivatives and integrals not determiners or minant i.e timelessness intent ,just only to see all in those plain of functionality coordinate in geometry or graphy

    • @diulaylomochohai
      @diulaylomochohai 2 года назад +2

      Whats 3b1b?

    • @angelinephilo2005
      @angelinephilo2005 2 года назад +5

      @@diulaylomochohai 3blue1brown, another maths channel :)

  • @jeremylevitt5492
    @jeremylevitt5492 2 года назад +26

    This is so well done. Covers a lot of intuition that many, many linear algebra classes leave out, leaving the students to decipher it on their own. Well made man, I really appreciate this video.

  • @derrylmartinez8010
    @derrylmartinez8010 2 года назад +48

    without exaggeration, this is the best explaining video on youtube i have ever watched. I have watched "Essense of linear algebra" playlist by 3blue1brown, but this is definetely more clear and understandable.
    I am very grateful for this masterpeace.

    • @mathemaniac
      @mathemaniac  2 года назад +6

      Thank you so much for the kind words!

  • @huitv1
    @huitv1 3 года назад +54

    wanted to just learn jacobian, but learned about linear maps and integral region mapping along the way, so cool!

    • @mathemaniac
      @mathemaniac  3 года назад +10

      Thanks so much for the appreciation! They are related concepts, so you would more or less have to understand all those concepts at the same time anyway.

  • @masonp5
    @masonp5 2 года назад +6

    I had never even thought about where the extra r came from when converting integrals to polar. This video just tied all of it together fantastically

  • @ryanj748
    @ryanj748 3 года назад +22

    This is one of the best, if not *the* best video on the Jacobian available on RUclips. Wonderful job here.

    • @mathemaniac
      @mathemaniac  3 года назад +2

      Thanks so much for the compliment!

  • @suyashgupta1180
    @suyashgupta1180 2 года назад +28

    I was able to solve these questions mathematically as taught by college profs., but never actually got the intuition of how things are flowing geometrically. Thanks a lot for explaining in such an intuitive way!

    • @mathemaniac
      @mathemaniac  2 года назад +4

      Glad that you can see the intuition now!

  • @zina2350
    @zina2350 2 года назад +7

    Thank you. Really educational. I came to this because I was reviewing my vector calculus course and I'm very confused about why is the definition of line integral and so on. This video gives me insights about the essence of derivatives & integration.

  • @ismagine
    @ismagine 3 года назад +32

    Thanks for the time spent in creating and sharing this video with meaningful insights of linear algebra, calculus, etc. Math is amazing and I’m glad we’re living in the time where deep math concepts can be explained clearly with aid of animations. Cannot judge all math professors for not having these tools decades ago and have to explain these concepts. But man , it really does a big difference.

    • @mathemaniac
      @mathemaniac  3 года назад +2

      Thanks so much for the compliment!

  • @alncdr
    @alncdr 3 года назад +34

    I'm so happy that 3b1b created manim as it's put to good use by many

    • @mathemaniac
      @mathemaniac  3 года назад +19

      Glad you enjoyed the video! Actually I didn't use Manim - will reveal how I make all these videos in the future.

    • @ankitaaarya
      @ankitaaarya 3 года назад +2

      @@mathemaniac thanks for clearing

    • @Xd4LEM4ObX
      @Xd4LEM4ObX 2 года назад +2

      @@mathemaniac I'm already crazy wanting to know it...

    • @revimfadli4666
      @revimfadli4666 2 года назад

      @@mathemaniac wait you have your own visualization library? Looking forward to that

  • @igorkuivjogifernandes3012
    @igorkuivjogifernandes3012 Год назад +1

    I love watch those type of videos. I remember when I took Calculus II in my undergrad in Statistics and had to use these jacobians to change the coordinates. This link with linear map was awesome!

  • @PaulFisher
    @PaulFisher 3 года назад +12

    As a bonus, your explanation at 19:00 also provides a nice demonstration of *why* the chain rule works. That is something I only truly figured out (beyond memorizing it and knowing *that* I had to use it) over the past year or so of casual thinking about math, after the end of my formal education!

    • @mathemaniac
      @mathemaniac  3 года назад +4

      Yes, that's also something that I have to think a lot more before making this video, because I never came across this explanation before, and had to think of this myself :)

  • @HorukAI
    @HorukAI 3 года назад +6

    I was smiling with resentment the whole video.. after aquiring master degree in theoretical mathematics, I realized I never really understood the concepts I know how to calculate the minute I woke up. That goes to the quality of my university, professors (with some exceptions) and my own will to go to the bottom of rabbit hole.

    • @mathemaniac
      @mathemaniac  3 года назад +5

      Thanks for the appreciation!
      I myself was not taught with this intuition either, so it just really takes a lot of time to actually think it through and thoroughly understand it, and to come up with a good intuition.

    • @ankitaaarya
      @ankitaaarya 3 года назад

      @@mathemaniac i can understand

  • @jewulo
    @jewulo 3 года назад +41

    This is a brilliant visualisation and analysis of matrix transformations

    • @mathemaniac
      @mathemaniac  3 года назад +1

      Thanks so much for the appreciation!

  • @ireallyhatemakingupnamesfo1758
    @ireallyhatemakingupnamesfo1758 2 года назад

    It’s been so long since I took multivariate calculus and linear algebra, so I definitely appreciated the little refresher on determinates and linear maps

  • @marti4
    @marti4 2 года назад +2

    Thank you for this masterpiece. I think that is the best maths video i've seen so far. The amount of understanding that you provided me with this video🤯. Keep doing this amazing work!

  • @py8554
    @py8554 3 года назад +17

    Before this video I only knew Jacobin and Jacobean. Now I also know Jacobian!

  • @l.p.7585
    @l.p.7585 2 года назад +4

    I did a course called dynamical systems and chaos in my second year of undergrad, and the ideas were extremely impactful but I had very few opportunities too apply them through the rest of a pure maths degree. In particular, linear approximations of non-linear approximations to inspect critical points for stability, bifurcation etc. This was the the method though

  • @wdavis6814
    @wdavis6814 8 месяцев назад

    That last section of the video blew my mind. I always understood the concept behind polar coordinates, especially their necessity for easing problems. But I don't think my college classes ever delved into the linear algebra explanation for it. Really cool stuff!

  • @CampingAvocado
    @CampingAvocado 2 года назад +2

    Your video series on complex calculus and this one has now given me an amazing visual understanding of derivation and integration and the connection between complex and real derivatives. THANK YOU

  • @marcushendriksen8415
    @marcushendriksen8415 3 года назад +14

    Well shit, here I was suffering through the Wikipedia definition for ages, when you come along and tell me that the Jacobian is just the best linear approximation for a function at a given point... So much more intuitive!! Thank you!

    • @mathemaniac
      @mathemaniac  3 года назад +2

      Thanks so much for the appreciation! Wikipedia does have this kind of intuition, just not in the Jacobian page, which is kind of strange actually: en.wikipedia.org/wiki/Derivative#Total_derivative,_total_differential_and_Jacobian_matrix

    • @carl6167
      @carl6167 2 года назад +1

      Yeah. Reading intuition off of equations really is an Art. It's a way of seeing beyond the formalism, which kind of is what makes maths so strong, but also very difficult to digest.

    • @joelcurtis562
      @joelcurtis562 2 года назад +1

      @@carl6167 It really is a valuable and pretty rare skill. For any important equation, I try to understand it by asking "How would I explain this to a child? To a high-school graduate? To an upper undergrad?" Pretty much just anyone who knows less than I do about it. That helps me get an intuition for the equation - where it comes from, how to use it.

    • @carl6167
      @carl6167 2 года назад

      @@joelcurtis562 the Feynmann method is quite cool because of that.

  • @bryanbowen4193
    @bryanbowen4193 3 года назад +3

    This is absolutely a work of art. It bridges the gap between intuition and practical notation with a splash of simple and beautiful.

    • @mathemaniac
      @mathemaniac  3 года назад

      Thanks so much for the compliment!

  • @Tiguiso
    @Tiguiso Год назад

    I just finished up Vector Calculus, and this is video has very much expanded my understanding!

  • @WhyneedanAlias
    @WhyneedanAlias Год назад

    I learned about this at the end of last semester. It was a lecture about applying higher mathematics (I'm in first semster) in a physical context and so we spent quite a lot of time on multidimensional integrals. At the end I had an intuition where these formulas came from but it would be much quicker I think if I had found this video earlier. So good stuff, your explanations are really helpful I think

  • @chrisb1047
    @chrisb1047 2 года назад +6

    This is crucial in understanding how to develop boundary fitted coordinate systems and grid transformation metrics in the field of computational fluid dynamics. When implementing a finite difference discretization on a non-rectangular physical grid it is necessary to transform the irregular physical grid to a rectangular grid in computational space. The transformations require the Jacobian! Excellent explanation ! Thank you

  • @scares009
    @scares009 2 года назад +9

    I'm going into my second year of undergrad in a few weeks. I can almost guarantee I will be referring back to this video once I get into the weeds of my courses. Thank you for making such digestible (and entertaining) videos, dude!

    • @mathemaniac
      @mathemaniac  2 года назад

      Hopefully it will be helpful!

  • @Joel-fs5zh
    @Joel-fs5zh Год назад +2

    thank you for what you do. I started college with a biochemistry major, but added on math because I fell in love with calculus.

  • @madmorto2610
    @madmorto2610 Год назад

    This really is a great video. I am only understanding it now, on my third watch. I watched it the first two times in high school, and now I am watching it again after learning basic linear algebra, partial derivatives, directional derivatives etc.

  • @kyleyan5974
    @kyleyan5974 Год назад +3

    One word.amazing! I come from China.And I major in math.I feel you just did a great job!❤❤❤

  • @balisto8374
    @balisto8374 Год назад +2

    You made a few things clicks in my head, you're a really good teacher

  • @guilhermegoncalvesalvarez3402
    @guilhermegoncalvesalvarez3402 Год назад +2

    Vídeo incrível! Tudo o que eu precisava!

  • @nils8950UTAUACC
    @nils8950UTAUACC 3 года назад +9

    This is such a nice way of thinking about u-substitution. I only knew the usual proof using the product rule, but that barely gives any geometric insight. Thank you for this visual intuition for something I thought was a purely analytic concept!

    • @mathemaniac
      @mathemaniac  3 года назад +4

      I assume you mean chain rule? Nonetheless, thanks so much for the appreciation! I myself didn't know about this insight before this video either, and I actually thought hard about it and came up with this explanation. Glad that you enjoyed it!

  • @adarshkishore6666
    @adarshkishore6666 3 года назад +20

    Thank you for the amazing content. Channels like yours have been an eye-opener for me in mathematics

    • @mathemaniac
      @mathemaniac  3 года назад +1

      Thanks so much for the appreciation!

    • @kopek702
      @kopek702 Год назад

      and how many degrees have your eyes opened my friend?

  • @pparsons12
    @pparsons12 Год назад +2

    These videos are a joy to watch. Thank you!

  • @FocusTokus
    @FocusTokus Год назад

    Thanks for the effort in creating these animated videos. They make math infinite times more enjoyable. I believe every math class should be like this. 👍

  • @Kanawanu
    @Kanawanu 2 года назад +4

    This makes so much more sense then 2 first years on my faculty through mathematics 1,2 and strength of materials. These transformations are very important in engineering science and using a dull textbook is not hettinf it close to students. I only came to understand at 28 through little trial and error at work what i was learning with no reference at 22. Only then it made sense and i was lucky to have come across it again.

    • @mathemaniac
      @mathemaniac  2 года назад

      Glad that you like the video!

  • @halikiidrisswouche6572
    @halikiidrisswouche6572 2 года назад +3

    Thank you to much for this setting :It helps me to have a good representation of the concept of jacobian and now i understand it deeply!Thousands thanks again !

  • @adjoint_functor
    @adjoint_functor 2 года назад

    INTEGRALS AS MASS MAKES SO MUCH SENSE, I’VE NEVER THOUGHT OF IT THAT WAY. YOU ARE A GENIUSSS
    Also thank you so much for this vid, Jacobians have been tripping me up

  • @dmitrystarostin2814
    @dmitrystarostin2814 3 года назад

    These were the last lectures on calculus at the Physics Department, 2nd year. This representation is a must for calculus.

  • @sudkun8420
    @sudkun8420 3 года назад +7

    This is a fantastic lecture with neat demonstration

    • @mathemaniac
      @mathemaniac  3 года назад +2

      Thanks so much for the appreciation!

  • @rsanden
    @rsanden 3 года назад +5

    Clear, concise, and well-done. I wish I had this 20 years ago!

    • @mathemaniac
      @mathemaniac  3 года назад

      Thanks so much for the appreciation!

    • @kopek702
      @kopek702 Год назад

      "clear, conscience and well done steak" used to be my racist great uncle's motto. I wish he could have read your comment 20 years ago before he succumbed to a wasp sting.

  • @jaimygebbeken8534
    @jaimygebbeken8534 2 года назад +1

    this really helps visualizing natural coordinates in finite element method, thanks!

  • @poqodobo
    @poqodobo 11 месяцев назад

    I never really understood determinant until I watched your video. This is amazing. Why can't schools teach it this way? Nobody mentions that determinant is the scaling factor in linear maps!

  • @nicholaswilliams4507
    @nicholaswilliams4507 3 года назад +9

    RUclips's algo is getting good lately. This was a term/topic that has been coming up in other studies of mine recently and your explanation was thorough and illuminating. I can think of many applications for this new knowledge. Thank you!

    • @mathemaniac
      @mathemaniac  3 года назад

      Thanks for the appreciation! Glad that it helps!

    • @dominicdellasera7397
      @dominicdellasera7397 3 года назад

      Same here!!! Studying for my Calc 3 test.

  • @nicolasflamel6518
    @nicolasflamel6518 3 года назад +5

    That's a lot of information and a lot of great insights for under 30minutes of video. With this high density, you can easily map this video to 50 pages worth of algebra textbook :-) Well done and thanks!

    • @mathemaniac
      @mathemaniac  3 года назад

      Thanks so much for the compliment!

  • @alogutz
    @alogutz 3 года назад +1

    Two words: simply brilliant.
    Loved the way you explain these topics.

  • @gokulaashiq9372
    @gokulaashiq9372 7 месяцев назад +1

    Really good explanation. Especially on that linear transformation part. Thank you. ✌️

  • @luci8952
    @luci8952 2 года назад +3

    The derivative in XY(2D) plane can be seen as "slope" and in the XYZ(3D) plane it is seen as "area". The same analogy is applicable for integrals: XY plane represent "area" and in XYZ plane "volume".

  • @usptact
    @usptact 3 года назад +4

    This is some _quality_ content! It indeed looks like a ton of effort went into making it.

    • @mathemaniac
      @mathemaniac  3 года назад

      Thanks so much for the appreciation!

  • @omarmoustafa6672
    @omarmoustafa6672 2 года назад +2

    Sir, you are a GENIUS. Thank you so much for your time and effort, this video clarifies many topics all at once. It was really a profound explanation that clarified many doubts regarding numerous topics. Thank you so much again for this video and keep up!!

  • @ingGS
    @ingGS 3 дня назад

    This is fantastic. We do essentially the same in Finite Element approaches to solve many engineering problems.

  • @brianlaw4706
    @brianlaw4706 3 года назад +12

    Excellent work! Just curious, are you using 3B1B's graphics framework for your visualizations?
    Regardless, love your videos and can't wait to see more!

    • @mathemaniac
      @mathemaniac  3 года назад +10

      Thanks for the appreciation!
      Not really - as said in the description, I will probably do a reveal of how I make these videos in the future :)

  • @im_rishi_speaks_ig8234
    @im_rishi_speaks_ig8234 Год назад +3

    That 'or is it ?' just destroyed my whole life

  • @yuwuxiong1165
    @yuwuxiong1165 3 года назад +2

    Great content. The concept of "linear map approximation" connects dots... now I know how to identify the "skeleton" of the linear map, which leads to the Jacobian... no more confusion on which indices run horizontal/vertical ... there are 4 possible combinations, and I was never able to remember it... Thanks!

    • @mathemaniac
      @mathemaniac  3 года назад

      Glad to help! It is confusing to memorise which variable to differentiate with respect to, but this hopefully helps!

  • @smaraggi
    @smaraggi Год назад +1

    I would have loved your videos in my University time. Excelent material, congratulations!

  • @abhaymanas7333
    @abhaymanas7333 Год назад +3

    derivative is scaling factor near f(x), then how the scaling factor was written to be 3 when derivative at 3 for f(x)=x^2=>f'(x)=2x=6

  • @user-or7ji5hv8y
    @user-or7ji5hv8y 2 года назад +3

    Lots of good intuition here. I would have never learn this without RUclips.

  • @CactuarTitan
    @CactuarTitan 2 года назад

    Wow, this is great for engineers who use visual learning, and translates effectively to how numbers are calculated algebraically in source code

  • @BitwiseMobile
    @BitwiseMobile Год назад +2

    oh gawd, as soon as you showed matrixes I was nope. I killed it in Calculus I, II, III, and IV. I went on to do just as well in differential equations. When I hit Linear Algebra though, I was brought to my knees. It just wasn't intuitive to me. Calculus made sense. Linear Algebra was my Kryptonite. Honestly I don't think learning Linear Algebra is the approach a beginning student should take to understand differential and integral Calculus. Coming at it from an Analytical Geometry approach is much more intuitive. It's easy to see rotations around an axis, or gradients, or areas under the curve. It's not easy to visualize an abstract idea like a matrix of numbers.

  • @kerty-
    @kerty- 3 года назад +3

    Thank you for the video and its subtitles!

    • @mathemaniac
      @mathemaniac  3 года назад

      Thanks for the appreciation!

  • @valasfar1557
    @valasfar1557 3 года назад +4

    I remember when you first made the announcement that you were starting a channel on Quora. I had been reading you for a while then so I’m very happy that you are getting some attention now :)

    • @mathemaniac
      @mathemaniac  3 года назад +1

      Thanks! You are an actually OG fan haha :)

  • @Saki630
    @Saki630 3 года назад +1

    This is one of the best videos on this topic. All it was missing was a really cool example of how you can change the integral to something easier. Polar to Cartesian and vis versa is easy to teach, but there are some cool ones that I have no idea how they were done that deal with non standard shapes.

    • @mathemaniac
      @mathemaniac  3 года назад

      Thanks for the appreciation!
      I don't know of any "cool" example for other changes of variables though. The reason why I specifically covered Cartesian to polar is simply that this is what we are going to need for the next video.

  • @zetzo27
    @zetzo27 2 года назад +1

    how have i never heard this interpretation of a determinant.. brilliant video

  • @mr_zmt7152
    @mr_zmt7152 3 года назад +54

    If you are still waiting for this to come out, you can drink something. stay hydrated... when you feel thirsty

  • @henrytjernlund
    @henrytjernlund 3 года назад +34

    I feel that about 11 min in, the material rushes forward more rapidly than the preceding material. I stopped the video there and will return to it at a future time. I guess I missed the part where why I would want to think about this as a map.

    • @alesjanecek9856
      @alesjanecek9856 2 года назад +3

      If I understand it correctly -> linear maps are easy, its just simple transformation and scaling. You can look at any 2D object as linear map as long as you zoom in enough. So you can forget about curves and just use simple transformation and scaling. So if you transform to polar coordinates you keep them information about diameter and angle in the limits but you look at dr*dtheta as rectangle instead of wedge.

  • @alejandromarmolejo7401
    @alejandromarmolejo7401 2 года назад +1

    Wonderful piece of explanation. I remember performing the computations in multivariable calculus at university without understanding the concept of the Jacobian. I guess content like this requires lots of preparation so thanks a lot

    • @mathemaniac
      @mathemaniac  2 года назад

      Thanks so much for the kind words! This video did take a lot of time and effort to make, so thanks for recognizing this!

  • @beauthetford7608
    @beauthetford7608 3 года назад +1

    25:45 that was the best explanation of the scale factor r and rdrd\theta. Never understood until now.

  • @strigiformsW
    @strigiformsW 3 года назад +4

    This is amazing man. thanks for making this. you're another 3blue1brown, Zach star in the making.

  • @joaquingutierrez3072
    @joaquingutierrez3072 3 года назад +4

    Amazing video!!
    I'm taking a Calculus III course right now. This surely is going to help :).

    • @mathemaniac
      @mathemaniac  3 года назад

      Thanks! Hope it does help in your course!

  • @AwaisKhan-mh6cd
    @AwaisKhan-mh6cd 3 года назад +2

    Best infographic and visuals in a maths video so exciting to watch keep up

    • @mathemaniac
      @mathemaniac  3 года назад +1

      Thanks so much for the appreciation! Glad that you like it!

  • @gusthomas6872
    @gusthomas6872 8 месяцев назад

    i took linear algebra and never learned these geometrical intuitions for linear transformations. thank you very much

  • @Tau-qr7f
    @Tau-qr7f 2 года назад +4

    I was taught to compute blindly all these nasty integrals, I feel these mysterious methods have been unlocked

    • @mathemaniac
      @mathemaniac  2 года назад +3

      Glad to help! Nobody should be taught to blindly apply something if they don't understand!

  • @dcterr1
    @dcterr1 3 года назад +4

    Very good video! I had several years of calculus as an undergrad and learned all this stuff years ago, but I still like how you presented it. Linear maps are indeed a useful way to think about differentiation and integration, even in 1D.

    • @mathemaniac
      @mathemaniac  3 года назад

      Glad that you enjoyed the video! Well, derivatives *are* linear maps in higher dimensions, so it is probably the way to learn about calculus anyway :)

    • @poulkasstill9380
      @poulkasstill9380 2 года назад

      And is the Base for the Math Language of Physics and Engineering of the Future ....The Differential Forms or The " Algebraic Geometry" or Cliffor Calculus....

    • @kopek702
      @kopek702 Год назад

      david terr or istanbul. Dont do it david

  • @siriuslydont
    @siriuslydont 6 месяцев назад

    I took 3d calc in freshman year (without linear algebra) and the Jacobian just felt like something I was supposed to memorize; taking a multidimensional real analysis course later in college, the explanation I saw was more akin to this, and it made so much more sense.

  • @a.m.2834
    @a.m.2834 2 года назад +1

    Great! Helps to understand the math in my first year in business administration (business engineering we call it).

  • @davecorry7723
    @davecorry7723 2 года назад +8

    In chapter 2, the scaling is 3. When the function is f(x)=x squared. Do the derivate is 2x. I couldn't figure out why the scaling is 3 instead of 2.
    It took reading a lot of comments to realise:
    1) The red point is 0, so the test value is 3. So the derivative here is 6.
    2) BUT The points are apparently only 0.5 apart, so the scaling is 3.
    Nope, I'm still not getting it. I'll come back after lunch.

    • @tibet_snowman
      @tibet_snowman Год назад +2

      The function f(x) = x squared has the derivative 2x for all x. So, when x=3, the derivative is 6. What does this mean? Consider x=3.1. f(3.1) = 3.1 * 3.1 = 9.61. Here, a change in x of 0.1 from 3 to 3.1 causes a change in y of 0.61. So, f is stretching the distances between these two points, 3 and 3.1, on the x axis by a factor of approximately 6. I think this is what the author here should be mentioning. Now consider x=--2. f(-2) = 4. f(-2.1) = 4.41. A change in x of -0.1 from -2 to -2.1 causes a change in y of 0.41. So, f is stretching distances in x here by approximately -4. Note that the derivative of f(x) at x = -2 is exactly -4.

    • @caesarxi1303
      @caesarxi1303 Год назад +1

      At 6:28 the value of a is 1.5.
      1- The function is f(x) = x squared.
      2- Near the point 1.5, the function is aproximately a line(the tangent line) --> g(x) = 3x-2.25
      He choses points next to 1.5 with a distance d between each other and calculate their value in the line:
      Points: 1.5-d , 1.5 and 1.5+d
      Values: 2.25-3d , 2.25 and 2.25+3d
      6:28-6:35 After mapping a to 2.25 through the function f(x) or g(x), its neighbours 1.5-d and 1.5+d are mapped through g(x). Its neighbours were at a distance d, and now are at a distance 3d.

    • @caesarxi1303
      @caesarxi1303 Год назад

      I'm sure a=1.5 because at 7:39 he makes a=-1 and f(a) = 1
      If a was -2, f(a) would be 4 and would be to the right of its actual value.
      f(1)=1 which is the only point that doesn't change (6:07).
      The yellow mark before one approximates 0(because 0.5 squared is smaller than 0.5)

  • @ninhingjan3237
    @ninhingjan3237 3 года назад +7

    The video recalls my university life of almost 50 years ago.

  • @moogzoliver
    @moogzoliver Год назад

    This is exactly what I needed to know. Thank you very much

  • @Redant1Redant
    @Redant1Redant 2 года назад +1

    T
    his is stunningly good. Really makes simple a sometime baffling subject. I found this very helpful. Thank you!

  • @akshatjangra4167
    @akshatjangra4167 3 года назад +136

    Vsauce music incoming in 1...2.....3...

    • @mal2ksc
      @mal2ksc 3 года назад +11

      Right after a dramatic "Or is it?"
      It got a good laugh out of me.

  • @marcelochirinoslazo5610
    @marcelochirinoslazo5610 3 года назад +6

    I'm only going to say Amazing dude!, I'm an undergraduate student in maths and the books some times are really hard to digest, have a picture of the sightseen helps a lot in the abstraction. Thanks!

    • @mathemaniac
      @mathemaniac  3 года назад +1

      Thanks for the appreciation!

  • @SaumenGupta
    @SaumenGupta 8 месяцев назад

    I could not take maths in secondary education, which i so wanted to ! But i think time is right to learn now. Thank you so much 🙏

  • @tamilselvanrascal5956
    @tamilselvanrascal5956 9 дней назад

    Really understood from the visually what we studied in high school n college
    ❤🎉👍

  • @PresCalvinCoolidge
    @PresCalvinCoolidge Год назад +4

    6:26 why does the Jacobian Matrix for f(x) = x^2 equal 3 instead of 2?

    • @mathemaniac
      @mathemaniac  Год назад +3

      It is actually (2a) at the point x = a. And so the Jacobian matrix changes from location to location. The animation just shows that the point is x = 1.5, and so the Jacobian matrix there is (3).

    • @PresCalvinCoolidge
      @PresCalvinCoolidge Год назад

      @@mathemaniac Thank you so much for taking the time to reply. Your explanation is exactly what had me confused but now I understand! Thanks again.

  • @ivarangquist9184
    @ivarangquist9184 3 года назад +5

    I think you survey could be improved a lot. I don’t think I’m the only one who have learned a lot of math through the math community (for example by watching math videos like these instead of taking classes). Therefore, I can’t really tell which subjects I have mastered and which I have learned all the basics of (perhaps I’ve missed something crucial). You could perhaps ask about what terminology we are familiar with, which concept we understand, and what impression a problem gives us (easy, solvable or scary). It would be easier to interpret, more useful and fun.
    Thank you for the video! I’m eager to see the final of this series.

    • @mathemaniac
      @mathemaniac  3 года назад +3

      You are not the only one in thinking that! I did originally want to make the form like what you said, but there are way too many concepts within each option, and I felt that it wouldn't gather as many responses because the form would be far too long, just for a RUclips channel, even though it is more useful to me. This is why you would have the option to tell me in more details what you actually know later on in the form. In that case, tell me that you have mastered the basics, but perhaps not completely.
      Maybe I could rephrase the options a little bit so that it becomes a bit clearer.
      Thanks for the appreciation of the video though!

    • @alexandertownsend3291
      @alexandertownsend3291 3 года назад

      @@mathemaniac just post a google form then you can make multiple questions

  • @user-yh6rv4bl4d
    @user-yh6rv4bl4d 3 года назад +1

    哇,太棒了,虽然没有完全解释所有东西,但给了我最最重要的灵感。我刚好被这个问题折磨好多天了。

  • @ahmedkhalaf9215
    @ahmedkhalaf9215 3 года назад +1

    I always knew I missed this information, but never knew where to find it. Thank you