What is a differential equation

[knightfightnight]

still dont know what it is.

[Omuniz1990]

Great videos. It helps review Differentials much faster!

[tadm123]

Brilliant video, can this man get a nobel price already?

[moomoorawrrawr]

you save my gpa again...

[engamin87]

Thanx!

[ivan765ful]

KHAN MAY BE CONFUSING SOMETIMES, BUT IN KHAN WE TRUSST

p.s wats a prime: '

[DonivDecap]

@ivan765ful

Example: Y' (Y prime) = dy/dx.



[mohdx7]

I wish to have you for all subject .don't stop

[loxaXcracker]

Dude... I fucking love you!!!!! You're awesome please never stop making these videos!!!

[mahirq8pk]

well for first i have 2 take the classes to understand ur writing then only i can come to this video..

[MochaJoe89]

my teacher actually told us to search up 'khan academy' if we didnt understand DE's haha

[adirajuadithya]

thankful to you!!!



[willghass]

It's dif-er-en-shal not dif-ren-shal.

[AbuFarisVehemently]

Nice Video, although I cringe when you say 'prime'. It sounds too united snakes of america lol

[AvanOman]

yah i see people have already posted good comments so I will keep mine simple.

I don't know what you believe in but this work your doing might get you into heaven.

Thank you like you like can't imagin :)

[cyberduck9]

You are a great man! :)

[sydneymassive]

What a life saver! You are a god among men.

[dasuperfly007]

Keep up the good work khan, man I can't imagine quiting my job to help teach the world but you did it.

And I appreciate it.

[SonOfNye]

Mr. Khan, you sir are a great man and an inspiration.

[dillonsterling]

Y prime is something you will Learn in calculus 1 so prolly your senior year. It is the rate at which y changes. Or slope of y at any given point. Y being a function.

[castronm69]

I'm in 10th grade.....what the fuck is y prime? :/

[arniehalpern]

@castronm69

Nice Talk.

[arniehalpern]

@castronm69

Nice Talk.

[G35saregod]

@castronm69 Y prime is the derivative of Y with respect to x. i.e., dy/dx is the most used notation in calculus. a derivative is the instantaneous rate of change, or the slope of y at any given point, or the tangent line at any given point, y being the function.

[castronm69]

@G35saregod

i know ur smart and all but can u speak in retard?

[G35saregod]

@castronm69 what do u want to know?

[hassanakhtar51214]

nice

[NuclearTide]

thank god for people like khanacademy and thenewboston.

[eliteeth4n]

i go to you instead of my professor who can barely speak english and has poor handwriting

[MrBanko8]

If math were my girlfriend, i would marry her now.

[erdwaenor]

It's good job, thanks for sharing such important information.

But I could only understand the explanations after

finishing roughly 1 semester of Differential and Integral Calculus initiation at my University; before that, most information on the video wasn't clear, or was in a explained in a way too advanced level jumping important Calculus fundamentals for the initiates.

But now (after 1 semester) however, I can grasp the ideas on the video quite well; and it's very useful.

[LittleAznMan]

wtf this guy sounds like that mexican guy who plays ssf4 gootecks

[johnnybygotz]

khanacademy is great!! I think that the BEST thing about you is how you take the time to ask aloud the "stupid questions" that we as students have. Where our college professors may have forgotten what it is like to be a student, and roll their eyes at us, you seem to voice EXACTLY what we are thinking. Kudos to you for being successful in making advanced math simple.

[JonhnyGrave108]

i'm gonna send this to my pretensious arrogant calculus teacher.

he cud learn a couple of things from u.

greetings and many thanks.

[osmamn]

@JonhnyGrave108 lol funny if he finds your comment hahahah

[xI777Ix]

Greetengs. Need help for a kind of differentials. For example: (x^2+1)^lnx or (x^2+1)^x. I think i have to make it with base exp, but i cannot do it by myself. Some advice how im suposed to solve these?

[aljon299792458]

man, u explain better than my professor

can u make a video on differential operators?? :))

[kid23gangster]

I bet those 13 haters of this video are TEACHERS. :D

[Steampunkfunk]

@kid23gangster Haha I had a teacher who often used the Khanacademy

[Khaelus02]

Just curious, which textbook are you using?

[Todoslosfritos]

he still has his text book from college!?! i lose mine before i even get to the final

[rafaelucf]

great video, looking forward to taking this class



[ACEWilly08golf]

Screw traditional education--Youtube=knowledge and knowledge=power!!!!!

[Kucho29]

There should be a khan in every school xD

[severrnijKGU]

next semester coming up and I gotta get an A in this. search for Scene - Happy Gilmore - Batting Cage and you'll get my mood.

[fatman1001]

what does "p prime" mean? 

[luckylogitech]

@fatman1001 prime is the "dash"over a  variable it represents 1st order for one dash 2nd order for two dashes and so on......hope this is helpful to you...

[scottdylan20]

My previous experiment will essentially demonstrate that Khan is the best teacher there's ever been in human history, and that the methods used in all academical levels from senior school to university are rather useless

[scottdylan20]

I reckon we could do an experiment: let's postulate two individuals of the same IQ and put one of them into a 4 year university course on mathematics only, and let's put the other one on a youtube course of about 3 weeks or so covering all of Khan's videos in the mathematics playlist (specially calculus); just about 3 weeks prior to the end of the other individual's 4 year course. They both will do an identical exam, and the individual who learned from Khan's videos will get a much higher score.

[SpoiledLogic]

Thank you for making this playlist, Khan. I am studying this on my own this summer and your videos are always a pleasure to watch.

And just cause I had to do it: Khhhhaaaaaaaaaaaaaaannnnnnnnnn­! ;)

[lindorchocolate]

Sign of an amazing teacher: I'm a junior in high school (16) and I understood everything you said in this video :)

[MrJongjongz]

can i download your videos for free.. because it is a very great help in my studies..

[itechkid]

@MrJongjongz yes he allows his videos to be downloaded. just click the "Show more" button under the video description. When that expands, you'll see a "Download" button in front of a blue background.

[Laimmemo]

AWESOME ! SO SIMPLIFIED,THANKS

[druebwake]

im in 4th year electrical engineering and i still dont understand D.E's lol...this has helped heaps thanks

[rv186rs]

So.. is it actually called "prime prime" for y'' in English or is it supposed to be "bis"?

[drrojas]

This might be the 100th time I COMMENT a vid of you saying : "IN KHAN WE TRUST!"

Youve gotten me past through Calc 1, 2 and 3 , Physics , and now Dif. Equations... class starts Monday , but at Khan academy CLASS STARTS Whenever I feel like , 3am thursday night? YES!!!

[SonOfNye]

I feel like subscribing to your channel sir.

[aragrox]

lmao I shine my lamp on my laptop at an angle and though it was a space background he was writing

[yoututorialman]

how do you write with the mouse?

Whats the name of the program?

Please help!!

[itechkid]

@yoututorialman From another comment on another video: He is writing on a virtual touch-pad-thing with a pen, that's connected to the computer. Even though it looks like he writes with the cursor, it's only a tool to make you aware of where he's working on the screen. :)

[yoututorialman]

@itechkid Thanks its because my father is math teacher and he think that it was nice to use!

[bukkworm]

@yoututorialman he's using Bamboo or some thing lie it

[GN0MEz]

i'm a freshman in high school in algebra 1 and don't uinderstand any of this, but i really hop to some day!

[ROXcursed]

This guy is an absolute hero. If you'd taken the time to see his later videos you'd see the quality improves dramatically.

[tahntalus]

hey sal, i was wondering if you could post a video on singular points, whether they are regular and irregular..thanks in advance!

[asfaqqq]

Please don't write with a mouse

[nicefriend7000]

helpful

[kilosaurus]

12 people that watched this are americans

[thunderbird5898]

@kilosaurus umm... what? way to be offensive, jerk

[ParadoxAnonymous]

@kilosaurus

How clever, did you come up with that one all on your own?

[PenguinFactory]

I have been looking for a video series like this for the past month or so. The ability to clearly explain maths concepts is so rare, it's great to finally find someone who can do it.

[cod4vsut3]

u sound like jeff goldblum

[masterbasser68]

well done! n i love how he calls them diffffrennntial equations lol

[92310CAMILLE]

wow,a better preparation for my incoming lecture in D.E.

[scout6686]

nice work khan! how bout partial differential equations?

[calipdis2]

what video follows this one? thanks :)

[sleepyhead7391]

1st day of classes = 1st day of youtube

[muzik123beat]

@sleepyhead7391 khan academy=mathematics academy

[enjoyablesounds]

if y' =-3e^ -3 .. isn't y' ' = 9e^ -4 ?

[ffrgtm]

@enjoyablesounds That's not how you differentiate when dealing with e. Remember an alternate form will be (-3)/(e^3)

[ffrgtm]

@enjoyablesounds That's not how you differentiate when dealing with e. Remember an alternate form will be (-3)/(e^3)..... the main thing to realize in your post is that there are no variables... the entire term you wrote is a constant so it will go to zero when differentiated.

[ffrgtm]

@enjoyablesounds you forgot the x in your post. Ignoring that, the derivative of e^x is (e^x)*(x)'

[enjoyablesounds]

@ffrgtm

thanks a lot! what a slip up!

[beenn15]

@enjoyablesounds if y' = 3e^(-3) then y" = 0

[warriorpoet575]

@beenn15 How do you get y'' = 0 from y' = 3e^(-3)? Check your math again, Salman is correct

[beenn15]

@warriorpoet575 my math is correct... and my comment wasn't a response to Salman.

I was merely pointing out that the derivative of a constant is 0.

if y'=constant then y"=0

[TheBalisto]

You are so incredible that you have 2044 videos of free lectures! You are the most knowledgeable person ever! And, extremely generous for doing these videos! :)

[toochameleon]

you are the best math teacher i've ever had. AMAZING

[ARYT13]

This guy is actually better than MIT's ODE lecturer. 

[datxcod]

@ARYT13 I don't get how anyone can learn from those MIT lectures. Those "professors" are responsible for people quitting science related careers.

[mustafahashimkhan]

10 people found this playlist after they failed in differential equations test

[ibikhan1234]

thank u teacher. luve u.



[NoobSidGuitar]

i want his college book :P

[bangthatdrumb]

why are they often written blah blah = 0

[azzam657]

Best explanation ever!

Thanks!

[S3851471]

Amazing

[deyomash]

why are all youtube "teacher" so much better than school "teachers"

[Cesariono]

@deyomash Because Youtube Teachers are too cool for School.

[alpineace2003]

@deyomash I don't know what it is with college professors, but they cannot teach! If it weren't for the free tutoring room and a few excellent engineering grad students from India; I wouldn't have gotten through any of my college math classes. Maybe we should integrate higher math at earlier ages in elementary school, or study math in our free time thorughout childhood, like Indians do.

[immortal6699]

WELL DONE....U HELPED ME ALOT

[kami645464]

One thing I have been wondering for a long time is how doe he write it with the mouse? Do you actually use a mouse to write it all? Or do you use a Pen Tablet to write it. If Pen Tablet, then how come we can see your mouse move just like an ordinary (without writing anything)?

I'm confused and don't understand it. Can you or someone else please clear my confusion?

[IGNsucks]

@kami645464 I was thinking the samething, I actually found myself mimicking the mouse movements to see if someone can do it that fast with a mouse.

[XDC3N]

@kami645464 a weird thing to wonder:) but he uses a some kind of pen tablet yes, and the mouse u r seeing doesnt exist in a lot of other videos, there s a crosshair instead.maybe the program he uses got updated or he had an error going on for several months i dunno

[beenn15]

@kami645464 he's using one of those Wacom tablets

[GotEnoughTay]

so if you were introducing differential equations to a 'struggling newbie', they would get it straight away? DON'T THINK SO.. I haven't got a chance :'(

[ny99999]

thanks a lot , I understood now what is differential equation and linear, nonlinear. I thought i will not be able to understand these things in whole my life cuz our professor makes it very hard , like this 1 + 1 = 9293 - 9000 - 200 - 90 + 18 - 19

[platinumgv]

@ny99999 YOU ARE SO DAMN RIGHT, EVERYDAY I'M THIS CLOSE TO QUITTING COLLEGE. I LEARN BETTER WITH YOUTUBE. In my case 1+1 = (5E3)/(dy/dt of 1000t) -(500E-2)+1(.5^2)(4) !!

[rushz0rz]

I love the way you say "Differential."

[Deniz1923]

This is great stuff... Thank you so much !!!

[TheBurningSeraphim]

y=0



[Zee96969696]

i didn't understand a thing, how from derrivatives get here to differential equatins?

[cantsitstill911]

@Zee96969696 looking for a general(or particular) solution for y that will satisfy the left side of the equation(plugging in the solution you found for y and all the derivatives) to equal the right.

[goodgoodgoodful]

Sometimes subconsciously I feel like to scroll up the video :) BTW, what a great and colorful lecture!

[eris4angel]

thank u man u are the answer for students who have professor incomprehensibile !!!

i hope some teachers can understand how a really teacher is !!

[MikeDunn]

@STEVEGET Steve, I agree 100%. Unfortunately, the degree is what gets you the job. But I honestly like to teach myself (if possible) which is usually doable with the right book.

[beenn15]

@STEVEGET liberal indoctrinators? what's so liberal about math?...

school is inherently liberal, it has to be if by liberal you mean: not limited to or by established tradition, views, dogmas, or authoritarian attitudes... free from bigotry...

school is where you have to question things to gain a better understand of how and why they are the way they are.

If we just accepted things without asking questions, we wouldn't make any progress, computers wouldn't have been invented

[Cathode0]

0:50 A differential equation is an equation that involves an unknown function and it's derivatives.

f'(x) + f(x) = x + 3 is a differential equation if you don't know what f(x) equals.

Rewritten... y(x) = f'(x) + f(x) - x - 3 and f(x) can be discovered (apparently).

Can you find f(x) in the equation y(x) = f(x) - x - 3??? (Where the unknown function appears only once in the equation, and with out any derivatives)

[cantsitstill911]

@Cathode0 for y(x)= f(x) - x -3, this is only a differential equation if y(x) is the derivative of f(x) of any order, or the other way around. otherwise the equation is a normal equation with 2 parameters. you can solve for the differential equation f'(x) + f(x) = x + 3 because it involves a function and its derivative.

[Cathode0]

@cantsitstill911 Hey, thx for your response. It wld seem then, that this vid doesnt show me the math I need. What I was trying to figure out was how to crack out an equation for something (here's a video of me asking the question if u got time /watch?v=jvo8SIU-nIg)

I'm basically trying to make an equation out of an observation. I have a hunch I should research Linear Algebra for clues, but I 'has no time' for that atm =(

got advice?

[chilionesaus]

Man, you're like the guy everyone hopes to find in mathlessons: crystal clear explanations, language that makes sense, good examples...You're helping me out time over time. Thanks for sharing your knowledge man, I really mean it

[Re1Mu2R3]

I wanna kick my teacher in the nuts after watching this. Bastard reads straight out of crap handouts...

[disornr]

Thx alot dude!!

[AlshokaniChannel]

Thank's!

But, when you say :"in the next video!" ==> i really don't know which one you mean?

by title? by sub-numbering clips? by date of post? by sequence in the right side clips?

i realy like your videos but i am totaly lost on how to know the actual next video from the list of clips?

kindly, if you can put numbering on titles such : 4-1, 4-2 , ..etc so, the viewer can know the number of topics related to each other.

Keep on please!

Regards,

Hamza

[stevemilwa]

@AlshokaniChannel google khan accademy, there all listed in order on his website

[wowggscrub]

this reminds me of integral calculus.

[meinefresse94]

I lost you at 4:48. now i'm gonna see the video again. And one more question: when do you start learning this in the USA? and btw you're great.

[mrmadmaxalot]

@meinefresse94 For math/physics/engineering majors (and maybe chemistry???) you usually do this by the end of your sophomore year. It is applicable to other fields as well, such as biology and economics, but you would probably need to minor in math to see it before the graduate level.

[horrabletypoe]

These playlists are amazing. My school did something strange with study designs, so instead of doing prerequisite materials before what they were required for, I'm doing the prerequisites AFTER the confusing and difficult topics which assume knowledge of them.

So this is pretty much perfect.

[gian123654]

nice

[farshadguitar]

thumbs up if you believe this guy deserves the nobel prize !

[ballsoffury4]

Do you know everything?

[yarahahrwe]

you are awesome

[mpetro202]

Sal, do you have a video on numerical simulation somewhere? I could not find any in the library?

[pkabooo69]

Khan Academy FTW!!!

[ahonsarkar]

Thanks to these lectures, I KHAN finally do Differential equations. you rock.

[Theincapower]

thank you sooo much!

[ronnieberner]

De"French"al equations. lol

[Bcboi92]

THIS GUYS WAY TOO SmART MAN

[InMarleyWeTrust]

you americans learn this in college? i'm sorry but i'm in england and we learn this in upper sixth or "our senior year of high school", albeit only in the further maths class.

[enjoyablesounds]

anyone know why the equation of the angle of a pendulum is a nonlinear equation?(this according to Differential equations for dummies) they claim this is non-linear because of the sin in the equation)...and in this video the yellow equation has sin x ( 8:39) and is referred to as "linear" :S..have I overlooked something?

[MrDesperateArtist]

the most famous Differential equation is the

Schrödinger equation! heheheheheh

[xfarahkhanx]

? ;(

[usenthemighty]

I love it when he says, " I' v run out of time". Where u goin we need you!!!

[styleguru1986]

hello Mr. Salman Khan , i first of all thank you for ur great help .

I have a question and i need its solution plz help me , the question is

y=(1+p)x +p^2 ; where p=y'

Thanks alot

[kirbz8888]

thanks for this...

[NissanAltima2005]

Very Nice,

It helps me understand D.E.

Thanks

[drewdah]

The project you have created is one of the most world changing things ever accomplished with the internet. One man is single handily changing the way education is dispersed and in doing so is bypassing traditional gaps in availability. Salman, keep up the good work and thank you!

[system0system0]

Why dont you try and make a fourier transform or DSP video a bit of college math or physics yes this is college stuff but basic stuff

[jauneliss]

why can't lecturers be like you? thank you for all tutorials.

[GdowProductions]

Heyy,

In which video u explain about the 'e'?

PLease because I'm looking for that video long time..

[sfrensley]

cows rule moo

[sirflysalot2111]

Awesome teacher! Thank you!

[GODyoutub]

you are the worst teacher ever

[jdiaz619]

im gay

[Huggy13ear]

My teacher blows compared to this guy

[Method9]

@Huggy13ear rewind helps too

[m2moun1]

he is better than my teacher in uni ... brilliant

[wildrider100]

great vid frm a great teacher

[kami645464]

This is 27 times better than my textbook. :)

[mrhnm]

Text books always have horrible explanations in them...

[heyyhowyadoin]

gracias guey muy buen trabajo con todo esto! de mexico!

lol jk im in america.

but good work keep it up.

[bountya1]

Bohat Aaala~!!!!! (Really great) ...YOu're Kkooool, from Pakistan :]

[shaunmikex]

I'll teach myself using these videos as opposed to listening to an incomprehensible 50 minute lecture. :-)

Thankx

[mrhnm]

Watching his videos allowed me to go from middle school level math to intermediate college algebra

[reclusivesage]

@shaunmikex You're so right, unfortunately. Math lectures are completely useless.

[kv310]

@shaunmikex you don't teach yourself. Internet - and in this particular case, Salman - teaches you.

[NMLP1]

@shaunmikex dude i feel that. at the end of this class i'm usually like...."wow, wtf just happened... YOUTUBE TIME!" seems like a waste. its 45$ per class at the 4 year university vs free lectures on youtube? why cant youtube give out degrees?

[sirachman]

@NMLP1 Totally agree with you. Sitting here watching these waiting for class to start... heh

[sam222ist]

Thank you so much! you are a very nice teacher.

best regards from switzerland!

[555mita]

"guru brahma guru vishnu guru devo maheshwara" greetings to u in sanskrit