Disc method around x-axis | Applications of definite integrals | AP Calculus AB | Khan Academy

Finding the solid of revolution (constructed by revolving around the x-axis) using the disc method. Created by Sal Khan.
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[@khanacademy]

We are contstructing a quarter at each x in our interval. The sum is the sum of all the "quarters" (each with depth dx).

[@Ben.N]

nice

[@junpark6892]

>cramming for ap calc test tomorrow
>1.5 speed
here we go xD

[@CrashingXSt0rm]

right there with you.

[@jjspear17]

1 year later. doing the same thing

[@darkensus]

Here we go again boys

[@royalekingdavid-clashroyal9088]

same bro 1.5x speed is perfect lol

[@RamanStudios]

Keeping up the tradition ...exam in 7 hours

[@jasmineampofo1102]

Thank you so much Sal, the formula makes so much sense now.

[@kevjtnbtmglr]

What program is he using? Sal is a good drawer.

[@suirahplanogemo3407]

I know I'm 5 years late, but whatever. He's using SmoothDraw

[@1gryphus1]

I thought he was a cabinet

[@ylvaeriksson5761]

There isn´t any good explanations in Swedish when you study math. Good for me is someones like you. :)

[@soulyest5167]

You help so many people. From the bottom of my heart, Thank you!!!

[@MrAlbashiri]

love you khan academy

[@zemotika]

I love how he teaches. Really wish more teachers and textbooks would be as effective as he is.

[@elite573]

I think it's just the different way he teaches. I bet if I had him as an instructor, I'd find someone who could explain some things better for me.

[@IAmTheGreatestThrill]

It looks like a Hershey's Kiss

[@KINGMUFASA]

Perfect explanation! Thank you so much!

[@zoechau8666]

This is new to me. I think it's amazing.

[@luvyjustinbeiber]

You make everything so much easier to understand thank youu

[@Engineering-To-Infinity]

I have been trying to understanding this for few days now, thank you very much mr Khan for making this crystal clear

[@darth009976]

Thanks it helps a lot!

[@kulvirjandir2454]

Thanks so much! Finally understand this.

[@metrix8155]

I would not be able to pass my calculus classes if it wasn't for you, thank you so much.

[@F3ver2Future]

Very clear, thank you!

[@houdinilinguine1073]

Thank you for the great visualization

[@tomaskvapil]

Thank you it is clear now..

[@xyz2007123]

Great! job Sal and Khan Academy

[@DaMan478]

So much better than my teacher...Thanks.

[@bettinatobias7040]

I understand what disks are now! 😄

[@AD-wg8ik]

A lot simpler than I expected

[@Ani-fq2je]

Thank you khan academy you saved me and I PASSED CALCULUS TODAY!

[@roaahedaya1779]

amazingly amazing 😄😄

[@EmmaRunningWeb]

Thanks!

[@nberz692]

OMG. Thank you so much

[@richphero106]

Beautiful illustrations

[@mubashir_usman]

thank you

[@MasalaMan]

when you got to the standard derivative stuff, I was like...what kind of witchery is this ?!?
Something i definitely need to look up

[@MateusOliveira-ho2wt]

very good!

[@rileylarch5417]

me trying to cram for my last ever calc grade tomorrow. I barely have a C rn. :(

[@Knightmare445]

thank you so much

[@zain4019]

Wow sals good at drawing

[@kingshill96]

please do a video on ricci flow. please :)

[@jp5568]

lovely

[@Sooooooooooorya]

"stretch our power of visualisation"

[@happyfrezar2813]

Thank u

[@terrynoah10]

How would you do this if the region crossed over the axis of rotation?

[@TheChris12590]

wizard hat

[@eunuchcommunity]

"...it looks like a little bit of a kind of a weird hat." - S. Khan

[@troyfitz1638]

Sal still the goat 🐐 8 years later

[@MohammedAhmed-dz2gg]

Amazing

[@tomaskvapil]

It is not true coin right? because radius changes when you move on x axes ....?

[@zbzb-ic1sr]

I was just wondering why these new videos are not in a playlist :/
I'm using software to download the videos in one go, it'd be more comfortable if they were placed in a playlist

[@Alduric]

what if you have multiple y = functions

[@shammu53]

Phil V that's the washer method

[@claudia-mr3tc]

Man this stuff is easy

[@nurulnajwabintihassanuddin5722]

Now I know why the name of the method is disk

[@justinrose5700]

wait, I thought dx doesnt represent delta x?

[@PunkHippie1971]

I must be clear. It is a wizard's hat. Not just any wizard's hat but Gandalf the Grey's hat.

[@martinronquillo7638]

literally the same prob Im doing lmao ftw

[@merdanchee]

why r=x^2 ??

[@merdanchee]

oh okay okay, understood, f(x)=x^2 thats why,

[@justinrose5700]

wait, I thought dx doesnt represent delta x?

[@larsheijne4586]

it does