Symmetry of second partial derivatives

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  • เผยแพร่เมื่อ 4 ต.ค. 2024
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    There are many ways to take a "second partial derivative", but some of them secretly turn out to be the same thing.
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ความคิดเห็น • 53

  • @maheryagub
    @maheryagub 5 ปีที่แล้ว +82

    Oh man, this voice. Greeting 3blue1brown

  • @omkumarsingh7
    @omkumarsingh7 4 หลายเดือนก่อน

    Thanks a lot for those two intro videos on partial derivatives, now I finally understand that what is a partial derivative both graphically and algebraically.
    I'm a high school student just
    I highly recommend you to not miss any of the last 3 videos before watching this.

  • @rajendrarai8190
    @rajendrarai8190 3 ปีที่แล้ว +9

    Could you plz analyze this fact with graph, excellent lectures.

  • @youneslamsaoui5242
    @youneslamsaoui5242 4 ปีที่แล้ว +6

    MAAN! You're an artist. I cannot thank you enough.

  • @derekwitzig9828
    @derekwitzig9828 8 ปีที่แล้ว +60

    +3Blue1Brown is it you?!

    • @금미경-o8c
      @금미경-o8c 7 ปีที่แล้ว +11

      Derek Witzig yeah it is him :)

    • @renzpaoloogena1900
      @renzpaoloogena1900 5 ปีที่แล้ว +3

      I immediately recognized his voice lol

    • @PranabMallick.
      @PranabMallick. 3 ปีที่แล้ว +3

      @@renzpaoloogena1900 Yup,me too

  • @elnurazhalieva1262
    @elnurazhalieva1262 6 ปีที่แล้ว +26

    Hi Mr., could you please explain that theorem which says that mixed partials are not always equal?

    • @lars1597
      @lars1597 2 ปีที่แล้ว +4

      satz von schwarz

  • @shreyankduttdwivedi2468
    @shreyankduttdwivedi2468 5 ปีที่แล้ว +5

    Please give a intution on second order partial derivatives

    • @satyamprakash7030
      @satyamprakash7030 4 ปีที่แล้ว +1

      This may not be the best explanation you ever hot however I will try my best. When we take the first derivative we are essentially asking what's the rate of change of the point to the point just slightly ahead of it. That's why it is df/dx, the df represent the change in function per the small dx change in the input value. When we say take the double derivative we are essentially asking what's the rate at which the rate of change changes. For that we have to take df(df/dx)/dx. In this scenario we are essentially taking the square of the tiny change in function and then dividing it by the square of the tiny change in the input value, that's why we got (df)2/(dx)2. Writing it like df2/d2x, in my humble openiun is just a matter of preferences.

  • @ΚωνσταντίνοςΛαζαρίδης-ξ9ι

    Grant for the win!

  • @MalkinsonJenkinson
    @MalkinsonJenkinson 10 หลายเดือนก่อน

    The cartesian refraction notation is partial by constant in diverse expression using dispersion in velocity to the quantities medium also geometric internals can concave convex bisector Abberation on filgment construct using ratio good luck

  • @huseynakifoglu
    @huseynakifoglu 8 ปีที่แล้ว +3

    thanks for perfect explanation

  • @felitham8685
    @felitham8685 5 ปีที่แล้ว +2

    Perfect
    THX from Thailand

  • @peternasser5171
    @peternasser5171 2 ปีที่แล้ว

    Watching this without ads
    I think youtube is gonna blow up

  • @elinanikolopoulou1769
    @elinanikolopoulou1769 2 ปีที่แล้ว +1

    Can you pls do some videos for 3+ variable functions ? I'm really struggling

  • @refugeec9669
    @refugeec9669 5 ปีที่แล้ว +1

    What should i learned to understanding this lecture help me!!!!!

  • @mrfares7271
    @mrfares7271 3 ปีที่แล้ว +1

    you explained it so clean

  • @NovaWarrior77
    @NovaWarrior77 4 ปีที่แล้ว +3

    COOL!

  • @dionsilverman4195
    @dionsilverman4195 4 ปีที่แล้ว +2

    I believe it, but why?

  • @jvanvynck
    @jvanvynck 7 ปีที่แล้ว +5

    Why didn't you take the second partial derivative of sin(x)(2y) at 5:33?

    • @avvvqvvv99
      @avvvqvvv99 6 ปีที่แล้ว +4

      because it's easy for you to make
      treat x as a constant, since it's multiplying, it continues to be sin(x)
      do a derivative of 2y and it's equal to 2
      so 2sin(x)

  • @tjm9951
    @tjm9951 2 ปีที่แล้ว

    Your tone puts me at ease with topics that would otherwise scare me off

  • @azizalaliq8
    @azizalaliq8 5 ปีที่แล้ว +1

    cheers mr 3b1b

  • @vijayanandvadhyar7224
    @vijayanandvadhyar7224 5 ปีที่แล้ว

    Excellent!!! Lots of love

  • @scholar-mj3om
    @scholar-mj3om ปีที่แล้ว

    Marvellous💯

  • @sergiosanchez5439
    @sergiosanchez5439 7 ปีที่แล้ว +5

    oh shit!! its my boy 3b1b

  • @baltofarlander2618
    @baltofarlander2618 2 ปีที่แล้ว

    But are partial derivatives commutative?

  • @curtpiazza1688
    @curtpiazza1688 ปีที่แล้ว

    Excellent explanation! 😂

  • @Ravstar999
    @Ravstar999 7 ปีที่แล้ว

    but why is this always true?? Is there anywhere I can go to get the intuition behind it?

    • @helenyao6513
      @helenyao6513 6 ปีที่แล้ว +1

      This is not true in general. Consider the example f(x,y)=xy \frac{x^2-y^2}{x^2+y^2} if (x,y)≠(0,0) and f(0,0)=0. You can find fyx(0,0)=1 and fxy(0,0)=-1.
      In fact, fxy (x0,y0)=fyx (x0,y0) if f(x, y) and its partial derivatives fx, fy, fxy
      and fyx are defined in a neighborhood of (x0, y0) and all are continuous at (x0, y0)

    • @Erik20766
      @Erik20766 6 ปีที่แล้ว +2

      That exact example is given on the Wikipedia page on the topic:
      en.m.wikipedia.org/wiki/Symmetry_of_second_derivatives

  • @সমুদ্রসন্তান
    @সমুদ্রসন্তান 3 ปีที่แล้ว +1

    He didn't completed the pyramid. :(

  • @isakhansen9572
    @isakhansen9572 ปีที่แล้ว

    Bro❤

  • @zes7215
    @zes7215 6 ปีที่แล้ว

    ts not fx or unf. not all purpox intex,notnex

  • @allaboutwindows1983
    @allaboutwindows1983 5 ปีที่แล้ว +9

    Please don't take trigonometric examples man.

  • @oakymcsd
    @oakymcsd 8 ปีที่แล้ว

    Golly

  • @raphaelbob8093
    @raphaelbob8093 8 ปีที่แล้ว +2

    first

  • @CONG001
    @CONG001 3 ปีที่แล้ว

    Bruh just use X and y as examples not sin💀

  • @jerrymahone335
    @jerrymahone335 6 ปีที่แล้ว

    Don't make it hard people. the first derivative is the slope of the tangent line, or the instantaneous speed, and the second derivative is the acceleration.

    • @xzy7196
      @xzy7196 4 ปีที่แล้ว +4

      What is the nth derivative?

    • @yashuppot3214
      @yashuppot3214 4 ปีที่แล้ว +6

      This is multivariable calculus.

    • @Jee2024IIT
      @Jee2024IIT 2 ปีที่แล้ว

      It's partial differentiation equation my man

  • @SooZoodimp
    @SooZoodimp 7 ปีที่แล้ว +12

    And what is the meaning of 2nd partial derivative ?
    I mean ... 1st partial derivative shows us a change of our function in certain direction, right?
    What 2nd derivative shows us?
    Thanks

    • @xoppa09
      @xoppa09 7 ปีที่แล้ว +7

      fxx is the concavity of f , in the x direction. And fyy is the concavity of f , in the y direction.

    • @bananian
      @bananian 6 ปีที่แล้ว +13

      It's the rate of change in the rate of change of a variable.
      Think change in acceleration.

    • @makotowang4363
      @makotowang4363 9 หลายเดือนก่อน

      The first partial derivative tells us the slope on the plane perpendicular to the x(or y)-axis, and The derivative of that ,which is the second partial derivative tells us the curvature on the plane perpendicular to the x(or y)-axis.(by the way, I’m 10 years old and I’m not lying)