The Convolution of Two Functions | Definition & Properties

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  • Опубліковано 9 лис 2024

КОМЕНТАРІ • 184

  • @ejkitchen
    @ejkitchen 3 роки тому +86

    As many others have stated, thank you for making this very easy to understand. It's fascinating how many bad profs there are out there attempting to teach this. If you think about it, it's not that hard but for some reason, many people struggle to explain this properly because they do not spend the time like you did to make it accessible. Again, thank you for doing this.

  • @vaibhavdlxit1050
    @vaibhavdlxit1050 2 роки тому +29

    You turned convolution from a dreaded enemy to an important ally which springs up to rescue while performing inverse laplace of evil looking functions. You sir, are a hero.

  • @nice4hat
    @nice4hat 3 роки тому +146

    I like your t-shirt haha

  • @bromarskiii
    @bromarskiii 4 роки тому +34

    You just explained convolution 100 times better than my textbook and my professor! Thanks!!

  • @ricardobautista-garcia8492
    @ricardobautista-garcia8492 3 роки тому +21

    Wonderfully explained. Time to do my final exam. Thank you once again.

  • @RubALamp
    @RubALamp 4 роки тому +2

    I hope you grow in popularity. Not that it should be needed, but I think many people would benefit from your insight. Thank you for your videos.

  • @josiahkolar4209
    @josiahkolar4209 3 роки тому +6

    This playlist and the ODE playlist have been getting me through this 5 week summer class

  • @migo77
    @migo77 4 роки тому +5

    Starting from 10:06 when you starting evaluating the integral & on the second line, the last part should have read: -0.5*TAU*cost t, because your're integrating w.r.t. TAU. Anyways, thanks v. much for all your efforts. God bless!

  • @sobhanboss3935
    @sobhanboss3935 4 роки тому +8

    this came in clutch, you made it so simple while my professor made it super confusing so thank you Trefor

  • @ConceptualCalculus
    @ConceptualCalculus 4 роки тому +15

    Just yesterday I was searching for a vid on convolution for my ODE class. Today this new vid popped up in my feed. I'm using it to replace the one I found yesterday, I suppose I should watch this one first, but that's not really necessary. If it is a Trefor Bazett vid, it is good.

  • @sarveshchandak
    @sarveshchandak 3 роки тому +12

    You cleared up all my confusion. Thanks a lot. ❤️❤️❤️

    • @DrTrefor
      @DrTrefor  3 роки тому +2

      You’re welcome 😊

  • @jaydean5243
    @jaydean5243 4 роки тому +8

    Dr Trefor, as usual excellent videos, If there are any math/engineering students that don't "Ace" their exams it is THERE fault...Great JOB !

  • @visualgebra
    @visualgebra 4 роки тому

    You and Dr Peyam have best explanation of Convolution!

  • @RanbirSingh-no3mc
    @RanbirSingh-no3mc 3 роки тому +1

    Best video on UA-cam till date

  • @DrDerivative
    @DrDerivative 2 роки тому +12

    if a = tau and b = t - tau, then how did you get b - a = 2tau - t? shouldnt it be t - 2tau?

  • @NPCNo-xm2li
    @NPCNo-xm2li 10 місяців тому

    You are single-handedly carrying all my math related subjects throughout my degree.

  • @Ayrmodros
    @Ayrmodros 2 роки тому

    Thanks so much. The example my teacher gived is so complicated and confusing. Your example helped me totally understand it.

  • @BentHestad
    @BentHestad 3 роки тому +8

    A quite difficult (but so essential!) concept very well explained! Thanks!

  • @zulhishamtan4308
    @zulhishamtan4308 2 роки тому

    Dr. Trefor....
    First of all, I like your T-Shirt.
    Thank you very much for sharing the knowledge.

  • @PiyushPastor
    @PiyushPastor 3 роки тому +4

    Wow. Only if the classes were this good.

  • @BoZhaoengineering
    @BoZhaoengineering 4 роки тому +16

    Professor Trefor your T shirt is fantastic. Can you please tell me where I can buy one?

    • @Tosti_bakker
      @Tosti_bakker 3 роки тому +5

      Same haha, I was looking more at his shirt than listening to his explanation

  • @eric_welch
    @eric_welch 3 роки тому +5

    Just got yourself a new sub :) thank you for the concise way you explain things

    • @DrTrefor
      @DrTrefor  3 роки тому +3

      Thanks for subbing!

  • @hsotnicam
    @hsotnicam 4 роки тому +5

    Little known fact: the verb for convolution is "to convolve," which means to roll something together. Although it absolutely also "convoluted" the two functions - meaning making something more difficult to understand, it is not what it intend to do :-D

  • @ProfeARios
    @ProfeARios 6 місяців тому

    Great video. Thank you for sharing. Regards from Panama 🇵🇦

  • @rmb706
    @rmb706 2 роки тому +6

    Believe it or not, probability brought me here. I was looking for a more rigorous definition of a convolution. I never studied the Laplace transform. Interestingly enough, two nonnegative RVs that have the same Laplace transform have the same distribution.

  • @eggxecution
    @eggxecution 10 місяців тому +1

    at 10:00 I think you made a mistake in trigo identity, it should be (a-b) also (a+b) to prevent confusion. This identity is product to sum formula if I recall correctly

  • @m7mdarwani964
    @m7mdarwani964 3 роки тому +3

    Clear and concise.

  • @manrajmann4732
    @manrajmann4732 3 роки тому +1

    love from India sir !

  • @ase1362
    @ase1362 2 роки тому +3

    You are of great help. Thanks

  • @JOAE23
    @JOAE23 5 місяців тому

    Well explained. Thank you!

  • @fernandogallardo3477
    @fernandogallardo3477 3 роки тому +2

    Good stuff for my signals and systems class.

  • @joaomattos9271
    @joaomattos9271 Рік тому +2

    Thank you very much!!!!!

  • @paulkanucawec9489
    @paulkanucawec9489 Рік тому

    What a concise explantation? Thank you Dr.

  • @JohnAbreu17
    @JohnAbreu17 3 роки тому +2

    Thank you for your great work. Probably missing a little comment about the Domain of *.

  • @johanfrancis2001
    @johanfrancis2001 2 роки тому +1

    Dr you really doing a good job...appreciate ur work.
    ..

  • @farukdemirel903
    @farukdemirel903 2 роки тому +1

    Great explanation! and also I liked the t-shirt..

  • @sergiopallas4567
    @sergiopallas4567 2 роки тому

    I'm sure I can't be the only one with this question. Where can we get that t-shirt? As always great video, thanks for helping those in need!!

  • @beophobic9653
    @beophobic9653 3 місяці тому

    Great explanations!

  • @TUCSKIRTHIKR
    @TUCSKIRTHIKR 3 роки тому +8

    Everybody : let us revise for tomorrow's exam
    Me at 12.am :

  • @amroalatasi2415
    @amroalatasi2415 2 роки тому

    That was very helpful Dr. Bazzet, thank you. Can you please send me the link of the shirt you’re wearing? It’s amazing.

  • @SHAHHUSSAIN
    @SHAHHUSSAIN 4 роки тому +5

    As usual outstanding...❤❤👏👏

  • @RAMKUMAR-rh4um
    @RAMKUMAR-rh4um 5 місяців тому

    Nice T shirt sir, covered all functions 😊

  • @codyfan1097
    @codyfan1097 2 роки тому +2

    Your videos are so helpful doc ❤️🙏

  • @thepie-phitalks07
    @thepie-phitalks07 2 роки тому +1

    Please bring a video on generalized convolution ( reference t. M Apostol)

  • @yuzou2008
    @yuzou2008 3 роки тому +3

    I love ur T-Shirt!

  • @vicadegboye684
    @vicadegboye684 11 місяців тому +1

    Where did you get that your shirt from? I love it. I was hoping to see it in your store. Would definitely buy it if you're selling it

    • @DrTrefor
      @DrTrefor  11 місяців тому +1

      My wife actually gave it as a present years ago and I've never been able to find the exact one again!

    • @vicadegboye684
      @vicadegboye684 11 місяців тому

      @@DrTrefor Oh no! 😭

  • @AS-bg9lg
    @AS-bg9lg Рік тому

    Hello, thanks for the video, I appreciate it!
    Btw, where did you get your t-shirt from? I like it, haha.

  • @philcooper279
    @philcooper279 2 роки тому +1

    Simply brilliant.

  • @master_zenrade
    @master_zenrade 3 роки тому +2

    Whoah T shirt 👚 contains summary of one year of Mathematics.

  • @matteodare1706
    @matteodare1706 3 роки тому +5

    this is what i was looking for! thank you for the amazing video.

  • @muhammadfaizan2232
    @muhammadfaizan2232 3 роки тому +1

    Clear and Great

  • @hectorgalva7495
    @hectorgalva7495 3 роки тому +2

    So good, so far. Awesome!!!😄😄

  • @gulsumsecilsermet8583
    @gulsumsecilsermet8583 5 місяців тому

    Thank you for the explanation. There is just one thing which is bother me. Sometimes speak rate is very fast then it becomes slow suddenly. Sometimes I couldn't understand that I needed to slow the video and it can be distructor.

  • @JuntaoChu
    @JuntaoChu Рік тому

    May I know where can I buy your t-shirt? It's so cute! (That blue one with many common math functions. )

  • @abang571
    @abang571 3 роки тому +6

    Dr, in your example, how can you get (2T - t) instead of (t - 2T) ? Help me out 🥺😭

    • @edilmarlulab7079
      @edilmarlulab7079 3 роки тому

      Use trigo. Identities
      from sin(T)sin(t-T)
      let A=T & B=t-T
      Then Subtract to get sinAsinB:
      cos(A-B) = cosAcosB + sinAsinB
      cos(A+B) = cosAcosB - sinAsinB
      cos(A-B) - cos(A+B) = 2sin(A)sin(B)
      sin(A)sin(B) = 1/2[cos(A-B) - cos(A+B)]
      Then Substitute: (A = T ; B = t-T)
      sin(T)sin(t-T) = 1/2{cos[(T) - (t - T)] - cos[(T) + (t - T)]}
      Then you get:
      sin(T)sin(t-T) = 1/2[cos(2T - t) - cos(t)]

    • @thejohncenafan100
      @thejohncenafan100 2 роки тому

      Cos is an even function therfore cos(x) = cos(-x) for every x in R.

    • @eggxecution
      @eggxecution 10 місяців тому

      I know what you meant fam, I saw the mistake in the video too. If you check the trigo identity he posted at 10:00 its (b-a) it should be (a-b) you'll arrive at 2T-t

  • @sujanban686
    @sujanban686 4 місяці тому

    I looked at your T-shirt more times than I used in the class.

  • @procerpat9223
    @procerpat9223 2 роки тому +1

    Nicely done

  • @asadshamsiev2462
    @asadshamsiev2462 2 роки тому

    Thank you Marc Gasol

  • @KhinThazin-nx8xd
    @KhinThazin-nx8xd 5 місяців тому

    Thank you

  • @j.o.5957
    @j.o.5957 3 роки тому

    Although I might not understand much of this yet, I'm beginning to grasp how to do the calculations

  • @sogol2261
    @sogol2261 2 роки тому +1

    Great video. 👍👍👍

  • @chinnamuniyandi2023jrf
    @chinnamuniyandi2023jrf Місяць тому

    If limit has between negative infinity to t in the convolution formula instead of negative infinite to positive infinite, should we call LTI system? Please reply.

  • @uchiha_kakashi6716
    @uchiha_kakashi6716 Рік тому +2

    so what is the difference between multiplication and convolution

  • @gregmcmahan7420
    @gregmcmahan7420 2 роки тому

    This is a great series. Stats question. Could you do a video on using the Laplace transform to get a characteristic function of a pdf?
    If possible, example 1 compares the moment generating function to the characteristic function of a pdf.
    Example 2 does a pdf with an undefined moment generating function to show how the characteristic function is more broadly defined.

  • @michaelholland5424
    @michaelholland5424 2 роки тому +1

    very nice video.

  • @x_ma_ryu_x
    @x_ma_ryu_x 3 роки тому +1

    life saver

  • @nnamdiYT
    @nnamdiYT Рік тому

    I heard another term called polynomial mutiplication used exchangable with the convulution.Are they the same or different?How do they relate?

  • @armanfahradyan6207
    @armanfahradyan6207 Рік тому

    Great video, but actually I think sin function on your T-shirt is flipped, it is -sin ))

  • @neptune8422
    @neptune8422 3 роки тому +1

    I like your T shirt!

  • @kenny44871
    @kenny44871 4 роки тому

    Great video as usual

  • @universalalgorithm3263
    @universalalgorithm3263 2 роки тому +2

    Why do convolutions need to be so convoluted?

  • @josephhajj1570
    @josephhajj1570 4 роки тому

    Oh thanks I'm taking electricity course and I'm using it very much

    • @josephhajj1570
      @josephhajj1570 4 роки тому

      @@DrTrefor yeah of course it's almost all EM based on laplace transform for signals....

  • @theblitz1687
    @theblitz1687 11 місяців тому

    this was great

  • @jacobanderson5693
    @jacobanderson5693 4 роки тому +1

    Thanks so much.

  • @tjk581
    @tjk581 3 роки тому +3

    I don't know. The definition of convolution is integral from 0 to t, or from -inf to +inf? In different sources, it's defined differently. Can someone explain?

    • @DrTrefor
      @DrTrefor  3 роки тому +5

      If f and g are zero for negative values, then they are the same and the int from negative infinity to infinity is the same as 0 to t

    • @tjk581
      @tjk581 3 роки тому

      @@DrTrefor But for evaluating convolution of f(x)=g(x)=sin(x) you used integral form 0 to t , when sin(x) isn't 0 for negative x.

    • @angelmendez-rivera351
      @angelmendez-rivera351 3 роки тому +2

      @@tjk581 But the Laplace transform only cares about the values of f(x) for positive x, so you can define f piecewise so that it is sin(x) only for x > 0, giving the result in the video.

  • @kexinsaw7092
    @kexinsaw7092 2 роки тому +1

    I like your shirt!

  • @superdahoho
    @superdahoho 4 роки тому +4

    nice shirt btw, where can I get it?

    • @rtusiime
      @rtusiime 3 роки тому

      I'm wondering the same thing

  • @raghuveerdani4046
    @raghuveerdani4046 Рік тому

    How did the sign of integral change? I did not get that part. What of we are integrating from -inf to inf??

  • @MrMobi007
    @MrMobi007 3 роки тому +1

    the only thing wrong with this video is we still don't know where to get the epic t-shirt.

  • @noureldinechaker131
    @noureldinechaker131 2 роки тому +1

    spent more time looking at the shirt than actually paying attention XD

  • @liheather2367
    @liheather2367 3 роки тому

    where did you get this Tshirt, professor?

  • @MisterBinx
    @MisterBinx 3 роки тому +1

    I need to solved this integral and it really confuses me. I don't understand that t-tau part being in the argument.

  • @prashantjoshi5389
    @prashantjoshi5389 Рік тому

    6:25 but why is L[f(t) * g(t)] = F(s) . G(s) ? Is there a different derivation for this property??

  • @accuset
    @accuset 2 роки тому +1

    I need a bigger numpad... dot product, cross product, scalar multiplication, convolution, holy crap.

  • @brandonklevans7473
    @brandonklevans7473 Рік тому

    Awesome shirt

  • @leixiao169
    @leixiao169 2 роки тому

    Where can we buy the T-shirt you wear ☺️?

  • @epicmorphism2240
    @epicmorphism2240 4 роки тому

    Fun question: A(f,g)=Lf*Lg
    What is A?

  • @SuperHovik
    @SuperHovik 2 роки тому

    How did you get -(1/2)tcost?

  • @jing-chingchen2333
    @jing-chingchen2333 4 роки тому +1

    thanks for the lecture for explaining convolution, but maybe need review a couple of times just to catch up with your fluent explanation......haha

  • @felixgomez5085
    @felixgomez5085 3 роки тому +1

    Nice !

  • @MachoMandem
    @MachoMandem 3 роки тому

    I subbed for the shirt, stayed for the video

  • @blackspitit
    @blackspitit 3 роки тому

    Hi, how is this related to a convolution in a Convolutional Neural Network?

  • @stringsam
    @stringsam 4 роки тому

    really well explained :)

  • @twillkickers
    @twillkickers 2 роки тому

    At 4:00, how does dtau turn into negative du? Where did the t go?

  • @ahmedesamamer
    @ahmedesamamer 3 роки тому +1

    Where can l get that T shirt ?

  • @rajkumarray2907
    @rajkumarray2907 4 роки тому

    How can we solve linear differential equations of first order derivative like - dy/dx - y/x = (2x) whole cube by Laplace transform. Please sir, plzz reply

    • @rajkumarray2907
      @rajkumarray2907 4 роки тому

      @@DrTrefor Thanks sir, i love ur channel. You are doing a great job.

  • @Acesushii
    @Acesushii 3 роки тому

    what about differential property? time shift and fourier ? halpp ;u;

  • @youreverydaytutor278
    @youreverydaytutor278 3 роки тому +1

    nice T-shirt

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

    🔥🔥🔥

  • @tesset8828
    @tesset8828 4 роки тому +1

    your shirt but y is the indicator function on a dense set :)