Limits are...weird...for multi-variable functions | Limits along paths

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  • Опубліковано 10 вер 2024

КОМЕНТАРІ • 83

  • @Rogue_Art
    @Rogue_Art 3 роки тому +98

    How does he take something so complex and make it so simple to understand? Absolutely amazing that Dr. Bazett is able to convey so easily in a few minutes what many professors can't in hours of lecture

  • @arshia1698
    @arshia1698 3 роки тому +17

    Accidentally coming across this video just a night before my Calc3 midterm was the best thing that could happen. Cheers!

    • @henriqueserra3233
      @henriqueserra3233 3 місяці тому

      same in calc2 haha. How did your's went 2 years ago?😂

  • @lutherlessor4029
    @lutherlessor4029 Рік тому +10

    Great "straight-forwardness" for picturing multivariable limits and great ending questions! I'm teaching multivariable calculus in the Winter and am using these as a refresher for myself. I've already seen some ways of presenting things that I'm going to use to improve my course. 👍

  • @geinezhang7030
    @geinezhang7030 4 роки тому +17

    the animation really helped me understand, thank you!!!

  • @mooseminddayan4650
    @mooseminddayan4650 3 роки тому +15

    Thanks a lot Dr. Bazett! The graph really helped me understand intuitively.

    • @DrTrefor
      @DrTrefor  3 роки тому +3

      Glad it was helpful!

    • @naveennaidu9064
      @naveennaidu9064 2 роки тому +2

      @@DrTrefor U deserve alot in heaven Dr .

  • @shonua5604
    @shonua5604 3 роки тому +4

    I used this for my midterms and I am back to it for my finals, and it is just as helpful each time (-:

    • @DrTrefor
      @DrTrefor  3 роки тому +1

      Good luck!

    • @shonua5604
      @shonua5604 3 роки тому

      @@DrTrefor Thank you!
      I literally have your line integrals video on right now!!

  • @sajjad213
    @sajjad213 4 роки тому +12

    in which video we're gonna answer to the those questions?
    thank you so much

  • @tb2748
    @tb2748 3 роки тому +32

    perhaps it would be best if some teachers could swallow their pride and instead just send a link to your videos :)
    well done, i'm starting to get this now at least from a conceptual viewpoint. thank you so much!

    • @daisyg509
      @daisyg509 3 роки тому +5

      I showed my professor (who is a great professor) his videos and told him that I use his videos to understand everything more conceptually, and he shared his channel with our entire class and linked them in our resources for the program we use.

  • @markbell8967
    @markbell8967 3 роки тому +1

    Failed out of Calculus 3 yesterday. I'll be here for the next 4 months preparing it to retake it next fall.

    • @DrTrefor
      @DrTrefor  3 роки тому +1

      damn, that sucks! Welp, good luck in the fall, I'm sure you can do really well next time:)

  • @shidaniell4538
    @shidaniell4538 Рік тому +1

    Thank you so much, I understand why multivariable limit is theta independent now.

  • @parkjessica4444
    @parkjessica4444 3 роки тому +1

    Thank you!! Explaining it with a actual 3-D graph helps a lot!

    • @DrTrefor
      @DrTrefor  3 роки тому +2

      You're very welcome!

  • @dankykong7676
    @dankykong7676 3 роки тому +2

    Could you add the subtitles, please? You're a great teacher

  • @jordanabarcelos3733
    @jordanabarcelos3733 2 роки тому +2

    Your videos are great. If you could put some translations, it would help many many more students. If you think about that, remember Portuguese, please. I want to recommend your videos to my friends, but they don't understand English. Just a suggestion.

  • @bishwajitsarma5768
    @bishwajitsarma5768 3 роки тому +5

    Rotational effect on the graph will be more helpful for better understanding

  • @gustavoavelino2718
    @gustavoavelino2718 3 роки тому +1

    Vamos de aprender calculo and english together, salve teacher leandro.... tudo our meu king

  • @vaishnavipal2298
    @vaishnavipal2298 2 роки тому +1

    How does one choose which path to choose to test for continuity, anyways, maybe I choose a bunch of different paths and get the same function value for all of them (get result that limit exists for that function), but still there maybe paths where it may be different, here I do not know what I don't know.
    It's a bit ambiguous

  • @lozy497
    @lozy497 2 роки тому +2

    This video opened my eyes :OOOOOOO

  • @martenschutte7182
    @martenschutte7182 3 роки тому +4

    How many of the same limit results do you need in order to conclude that the limit exists. For example taking the 2 paths allong the x axis and the y axis is not enough right?

    • @DrTrefor
      @DrTrefor  3 роки тому +5

      Even a million paths wouldn't be enough. That's why we have to either use some proven algebraic rules or prove it from the limit definitions directly. It's not easy!

    • @AtakanG.
      @AtakanG. Рік тому

      we learned this topic today , the way we chose was to use squezee theorem

    • @mangatram3389
      @mangatram3389 Рік тому

      Sir, why we can't prove it by y=mx, if limit is free from m. Please sir make video on this topic. I am going to die for this question.sir please, please,

  • @continnum_radhe-radhe
    @continnum_radhe-radhe 2 роки тому +3

    Sir, absyln delta definition of limit??

  • @nikhiltrehan96
    @nikhiltrehan96 4 роки тому +6

    Great content! Just a quick question, how do you prove that the limit does in fact exist? Because failing to prove that the limit does not exist does not mean that the limit exists, how would you go about proving it if plugging in values of x and y results in 0/0 or something along those lines?

    • @mahdi7d1rostami
      @mahdi7d1rostami 3 роки тому

      i don't know answer to this question in multivariable calculus world. but in calculus 1 in university we thought to prove limits and it was only acceptable answer and just calculating wasn't acceptable. the way it work was as following:
      by considering any value for instance _a_ we should show that there is a value such as _b_ where:
      f(x⁰+b) < a
      ultimately the job was to find a function to find _b_ based on _a_ and showing for every _a_ there is can be a _b_ founded. it was really hard to understand and solve problems in this way.

    • @goddess_ofchaos
      @goddess_ofchaos Рік тому

      i know that using direct substitution resulting in 0/0 means you need a different approach, e.g. manipulating the function by e.g. factoring things out, L'hopital or you could try to look at the limit of the function along the line y = ax where a is just any constant in R and y = ax^2. Usually these two are enough to show that the limit does or does not exist. There is a more accurate proof for this (i think it is called the epsilon delta proof) but I'm quite unfamiliar with it. Another way is to use the intermediate value theorem and setting one variable to be greater or equal to another (this is is most commonly used when the limit of the variable goes to 0 so we can compare the two limits).

  • @alkankondo89
    @alkankondo89 4 роки тому +2

    This type of limit IS weird! It makes sense, though, since this particular limit is of the form 0/0. It can have multiple values and is thus indeterminate.

  • @nonentity168
    @nonentity168 10 місяців тому

    Great lecture with incredible effort, thanks

  • @JavSusLar
    @JavSusLar 2 роки тому +1

    Dr. Bazett, there are tricky equations with tricky points that don't have a normal vector, even if they seem smooth and well behaved. For instance, consider z=(x^3-3xy^2)/(x^2+y^2). It is easy to see that z=0 at (0, 0) , since every limit converges to that value. It is also differentiable at that point. But it has three-fold symmetry around that point, so no plane fits as tangent. How should that point be treated? In particular, normal vectors define in optics how light reflects off a mirror. If a mirror was made with that shape, how would light be reflected at that point?

  • @sandrashappell6754
    @sandrashappell6754 Рік тому

    You are excellent at explaining!

  • @mikiti6870
    @mikiti6870 10 місяців тому

    let's consider this function f(x,y)=x*y/((x-1)^2+y^2) and (x,y) approach to (1,0) then what path can we take? Can we still take y = x or should we take for example y= x -1?

  • @michaelrafales2782
    @michaelrafales2782 9 місяців тому

    Just found your channel.
    Very nice videos and explanations!
    Thank you

  • @nik7729
    @nik7729 3 роки тому +3

    no permutation or combination of 26 alphabets can define how good you teach , I'm not jokin it was actually too good

  • @johannhernandez583
    @johannhernandez583 3 роки тому +1

    this idea of restriction is just cool

  • @marekglowacki2607
    @marekglowacki2607 4 роки тому +2

    Please postprocess audio to remove this empty room echo effect. Beside this your content is great :)

  • @EricPham-ui6bt
    @EricPham-ui6bt Рік тому

    The best way maybe average contrast of each dimension will intersect at centroid then use that as objective reduce the computation in computer time because it expensive

  • @kasyapdharanikota8570
    @kasyapdharanikota8570 3 роки тому +1

    wow !! very good graphics and explanation

  • @omarayoubi8135
    @omarayoubi8135 3 роки тому +5

    how can someone dislike that 😂

  • @thisukainol
    @thisukainol Рік тому

    Guardian angel professor ❤

  • @sanelprtenjaca9776
    @sanelprtenjaca9776 4 роки тому +2

    Trefor, I think path can't be curvature that is not continuous (because that would cause problems for h --> 0), but I am not sure. Also, if curvature is differentiable, then (for h --> 0) we can aproximate it by some streight line and that we can easly solve. So, does curvature (path) must be continuous and/or differentiable? Thanks

  • @continnum_radhe-radhe
    @continnum_radhe-radhe 2 роки тому +1

    Thank you sir 🔥

  • @aleynaozer
    @aleynaozer 10 місяців тому

    Thank you teacher. 🎉

  • @niom9446
    @niom9446 2 місяці тому

    what are the answers to those questions at the end?

  • @shubhammittal566
    @shubhammittal566 Рік тому

    Sir, is there a condition that the curve along which we approach should be smooth? Because otherwise there can be many path along which any limit would not exist

  • @munozali1
    @munozali1 3 роки тому +1

    That's true about other instruments, to an extent.

  • @rumblebuble837
    @rumblebuble837 3 місяці тому

    Can someone plz explain why the 0,0 of y and x arent a same point ?

  • @OseiKwakuTanoh
    @OseiKwakuTanoh 3 місяці тому

    Very nice video ❤

  • @raunitsingh676
    @raunitsingh676 2 роки тому +1

    loved the video 👍👍👍👍👍

  • @mangatram3389
    @mangatram3389 Рік тому

    Sir, please make a video on last two questions. Sir please😭😭😢😥😭😭😭.
    Sir, if limit is same with all paths along the line, would it be same along any curvy path.

  • @just_another_guy6915
    @just_another_guy6915 4 роки тому +2

    great stuff.

  • @akshitabatra2500
    @akshitabatra2500 3 роки тому +1

    Great explanation

    • @DrTrefor
      @DrTrefor  3 роки тому +1

      Glad you think so!

  • @mangatram3389
    @mangatram3389 Рік тому

    Sir, how can we contact with you.

  • @federicopagano6590
    @federicopagano6590 2 роки тому

    What is the difference between the limit and the continuity definition? One could say in the continuity definition we add the last term L(left)=L(right)="F(xo)"and in the limit definition we dont use the last term thats the only thing and thats wrong thats why if we are asked about this exact example about continuity at the origin the question has no sense at all. And what about if we are asked about the continuity in general of
    f=xy/(x^2+y^2) of course it is!!!

  • @krupt5995
    @krupt5995 2 роки тому +1

    What software are you using for the 3D graphs?

  • @zaker6257
    @zaker6257 3 роки тому +1

    tbh, i came to find answers to the questions myself.
    Anyways, thanks.

  • @Jack_Callcott_AU
    @Jack_Callcott_AU 2 роки тому

    I wondered about Question 2; my intuition says that, yes, a limit would exist if the approach on every straight line yields the same result.

    • @lightspd714
      @lightspd714 5 місяців тому

      My thought was that if you approach the limit with all combinations of straight line paths and they all converge to the same value then approaching along a curved path would also yield the same value and the limit would exist. May be there is more to it though.

  • @EricPham-ui6bt
    @EricPham-ui6bt Рік тому

    That is green theory was introduced but I called it là grange theory

  • @ruby-oo9fi
    @ruby-oo9fi 2 роки тому

    wow it's math pewdiepie. damn he explains stuff so well...

  • @ButerWarrior44
    @ButerWarrior44 2 роки тому

    so you can make y = any type of 'x' ??

  • @lucieneyvrard5414
    @lucieneyvrard5414 3 роки тому

    Another time unbelievable content
    However at 2min54 if you plug y=-x the denominator will not be wero ?

  • @MonkoGames
    @MonkoGames 3 роки тому +1

    so the limits kinda like a volume/ area

  • @Aim4sixmeals
    @Aim4sixmeals 4 роки тому +1

    New sub here!

  • @malakasadalikhan109
    @malakasadalikhan109 Рік тому

    1:15

  • @abdullahtahir488
    @abdullahtahir488 3 роки тому

    who are these 5 people? :)

  • @abc_cba
    @abc_cba 4 роки тому

    I just love your videos. Is there a way to take you out on a date ? 💓

  • @moinshaikh1963
    @moinshaikh1963 3 роки тому

    4:15
    multivariable function... such a hypocrite!!!

  • @yasmeenali7899
    @yasmeenali7899 4 роки тому +3

    He’s hot I can’t focus

    • @noufkhalidd5654
      @noufkhalidd5654 4 роки тому +1

      XnotYas i cant stop staring at his beard

  • @RobertOppenheimer-of6gu
    @RobertOppenheimer-of6gu 2 місяці тому

    SCAM VIDEO!!!