Introduction to the Convolution

[marcalanstreeter]

Great tutorial - and thank you for the small refreshers in the middle - its been a while since I had used them

[toridvoice]

This is extremely helpful.

Next video of high level math could you not go over U substitution... or explaining the other math... I mean I assume all of the people that come here are engineers... or at least have other sources of calc 1 or 2.

[DiggOlive]

@redougulas You wouldn't have been able to hear Khans voice in this video if it were not for the convolution.

[sandslash123]

You should have rather showed how it behaves on a graph instead of manipulating trig identities for 10 minutes. Nonetheless, thank you!

[DasGewitter83]

great example! Thank you very much for helping me understand this concept:)

[uulises1]

THANKYOU!! sooo much

[kungman190]

still didn't get this concept 

[redougulas]

anyone else feel like math like this is a waste of time?

[WahPetz]

@redougulas Absolutely not, this has a lot of application in electronics believe it or not.

[seanrichardsdubai]

* exercise 

[emiliejolie369]

It's absolutely rubbish. There isn't any explanation of what it is. He is just doing an "exercice".

[holymasteric]

the verb is convolve, not convolute

[Bearkiller777]

Thanks Sal. This helped me understand convolution

[kourosh89]

f*g looks like fag

[binvid]

Thank you very much. GREAT Tutoring.

[davidlamys]

people should just stop whining..one reason why youtube may be better for learning is that if the tutor is going too slow for you, just hit the fast forward!!!

[thomaszweef]

thank you! This video helped me so much in understanding convolution

[Lanza52]

I love Khan Academy and all the work does... but I feel he severely overexplains things. If you are learning convolution, you have no need to be explained u substitution or basic trig identities. This video had about 7 minutes of substance and 11 minutes of Sal babbling about highschool trig and calculus.

[foosta5]

8 people are not engineers?

[securezone]

@foosta5 only 6 people are engineers?

[richlong28]

mind... blown

[Arminpars2]

the "whole hairy problem" that lasts 19 minutes would be done in 3 minutes if you were to rewrite the integral "sin(t-tau).cos(tau)" as integral:

"1/2*[sin(t) + sin(t-2*tau)]"

and integrate them separately i.e. :

"1/2 int(sint * dtau)" + "1/2 int(sin(t-2*tau)*dtau)"

where "int" stands for integral.

[blackcan1189]

lol , whenever he writes sin t

it looks like it says slut

[isam1335]

you tau tau huh? lol

[BlackBile666]

I can not believe how helpful this would have been if I had youtube when I was at uni.

[DrFlox]

For a future video it would be great to see a visual explanation of convolution, what is actually happening with the functions?

[janitarjanitar]

towards the very end.. sal turned a sum of two trig functions into a product of two functions.. because he can.

[linuxuser5]

thaaaaaaaaaaaanks man , you are the best !

[meme2342]

Excellently set out. It especially highlights the need to check your workings. Lol.

Do you have any videos showing how to convolve 2 non-periodic functions, such as a triangular pulse and a gating function, please? I get confused where different limits of integration apply to different areas of the process.

[giancarlocpy]

wooo, excelent.

can you tell me which software do that?

[111Prince111]

omg u just helped me so much n my web hw, this is why i love youtude seriously

[3554280]

aptly named, the convolution integral

[Ritzoid]

This video should explain what a convolution is and what it is doing (Using analogy... not math). This would give a much better insight on the concept.

[0lMelhor]

Obrigado !!! Muito bom, Very nice :D

[jengativ]

thank uuuuuuuuuuuuuuuuuuuuuuuuuuu

[camilo7456777777]

muy bueno gracias

[vsimoul]

i am a big fan of khanacademy BUT this was a really bad introduction to convolution, it was a nice example of how you calculate a convolution but this is not a good way to introduce a mathematical concept

[ronijun888]

Thanks.....

[subwaynorth]

Nice!

[bla7091]

It was more of an integral and geometry lesson, things I learned way before the concept of convolution came up. If the title changes, this will be a great example though

[carlosjosepxd]

better than my teacher :P

[sharikamesba]

excellent video! Thank you =]

[postigaceltic]

I don't know about you, but I only learnt about that in the last year of high school before entering college, which was this year, so it's quite understandable. On the other hand, you do seem to have some unsolved issues. Who are you to be on the internet judging other people's comments, let alone be upset by them. I never felt like a retard until I got trading messages with you. There's a life out there, son. Get a girlfriend and let the jerk-off time for later. See you in NASA, geek boy.

[postigaceltic]

@bcosby5252 I'm sensing some internet toughness here, am I not? I'm guessing help would be necessary if you start randomly insulting people you don't know on the internet, "retard". Are you not confortable with who you are? Well, it's not my fault. Now, I don't remember asking you for an opinion, so please shut the fuck up.

[Gaussdxdydz]

Hi Sal. Thanks for all your nice videos. I would just like to ask you whether it is not simpler to integrate sintcost by re-writing it as half sin2t rather than use substitution as you did. Kind regards

[einsteinino]

By means of Werner formulas, the integral for the convolution would require way fewer steps in order to be calculated!

[Ibriam]

Hello. First of all, thank you for the video! I have only one question for you. What program do you use to write into the computer?

[lightfootharry]

this video was really helpful to me, however i would just like to know what it *actually* means (if anything) that the convolution of these functions gives that result

[Ronaldoh1]

who ever you are ...i just want to say that you're awesome!!!!! love you man thanks for the vids!!

[postigaceltic]

Hey, I just think you should have made a more simple example without the sen and cos for begginers like me, cause that's really distracting and we easily lose the track of the main thing (the convolution)

[gremlinextreme101]

@postigaceltic If you can't deal with these simple integrals you should probs not be studying this topic. Not meaning to sound harsh but they should be second nature by the time you're on this kind of topic

[postigaceltic]

LOL! Are you mad today or you're always like that? Sorry, if I'm still a student and had to learn the Convolution TWO MONTHS ago by myself. When I made that comment, I was trying to learn the Convolution steps for the first time, and if you're so smart, then you will agree with me that when you're trying to explain it online, it would be way more simple to take off those sens ans cos, cause like I said two months ago, they are distracting from the main subject, the Convolution. Bye.

[postigaceltic]

Oh, and English is not my mother language (actually, far from it) so I had to deal with that as well. I'm gonna give you an advice, don't act so smart on the internet, you're only making yourself look like a big, giant vagina.

[gremlinextreme101]

@postigaceltic Insulting people giving you constructive criticism is not generally advised. I too am enthusiastic about calculus and have taught it to myself for the last two years from videos online. One of the first (and most difficult) things is to establish a general order in which to learn the topics, now I have no idea why you would want to know about convolution (trig integrals should certainly be learned first), but criticizing the makers of free videos is fairly ungrateful act.

[postigaceltic]

I'm at loss of words. Are you mental or something? Yes I did insult you, but give me a break, I would do it again, cause you were attacking me first. You're NO ONE to tell people what they should or not be doing and you surely are not the one to tell me if I'm on the right topic or not. You don't even know me or the circumstances. And the part of your "constructive criticism" actually made me want to slap you. Please stop sending me these messages, are you some kind of stalker too?

[postigaceltic]

I learnt trig. integrals WAY before I even heard about Convolution. I don't get all my information from the Internet *rolls eyes*. I wanted to learn the Convolution and had very short time to do so (why, doesn't matter to you) and I surely didn't want an example with 28minutes so I asked the author to get rid of the sujacent matter (this is a constructive criticism). If you don't understand such a simple situation, I fail to see how you even dare to criticize me for any other matter. Bye.

[gremlinextreme101]

@postigaceltic stfu you immature little child, I'm sick of people like you ruining the great opportunity the internet presents for education. You know when there's a communication breakdown due to a medium like this both sides should acknowledge it. I am sorry you misunderstood my initial comment but you have no right to hate on me for it. If you don't like advice then don't take it, but think of how slow the world would progress if people were afraid to advise, thanks to response like yours.

[postigaceltic]

Hey hey, I think you should really calm down there dude. Tough one on the internet, aren'tcha? Is this even allowed here or something? I already said for you to stop sending me messages. Go somewhere else man.

[mldmiza]

i understood how it is done but i still need to know what is a convolution.

[outinaustin]

Should have picked an easier problem that does not distract from the topic.

[axiomsofchoice]

Excellent clear presentation. However it would be better titled as "Convolution worked example" as I don't feel I could understand from this video alone what convolution is doing to the functions it operates on or why I would want or need to use it.

[sizzlingal]

Thank you so much! like everyone else, i did not understand what my Professor has been talking about all semester! If i didnt watch these videos, id have no understanding of Diffeq's. May you be blessed for posting these videos!

[gefallt]

This is where it gets HARD

[MatrixOfDynamism]

the cross hair should be made invisible.

Please do that.

[redshot17]

Finally I understood how a Convolution is done.

Thank you very much.

[sisip123]

this is the best! thank you

[BluesMan2]

Thank you so much :)

[1carlento]

I'm doing my second year mechanical engineering at university and this is helping me a lot thank you very much for posting this amazing clips.

[shazaduh]

Very nice video and please do make a video on Convolution intuition.

[try555555]

very nice , i want also ask the same , please , make a video on Convolution Intuition , thx

we are witing for it :)

[ad2181]

Sal,

As a DSP EE this is the most important concept ever.

[abuhajara]

yes, because if you have real time problem. For example, if you using real time microprocessor, you may get around FFTs by using convolution, specially if you are using FIR filter.