Solid of Revolution (part 2)

[KhaosSoulFury]

lol you should definitely pick up a copy of mathematica and just copy the graphs beforehand. these are a huge help.

[nicayat]

i love your side comments on your circle tools! i mean this subject is suppose to be fun right ?!

[654Tye654]

Between you and patrickjmt I am really understanding calculus.

[JohnBarchard]

I like watching you keep trying to draw that nice cup at 1:37

"This is excellent. This tool is very well suited for what I'm doing here." 2:12

[Dano9102]

Thankyou very much, as you said, actually understanding why it works makes it a lot easier to use, i was slightly confused (Despite have the formula in a formula booklet for my exam) but now that I understand it, questions seem a lot easier.

im sure you've been told enough how great your videos are :) But still. THEY ARE GREAT

[Seguris]

Amazing video. Just wondering, why don't you include the 'dx' of the volume function when finding its integral?

[Vinco]

@Seguris in a simple case like this, i don't think writing it would have been necessary.

[jakemaxhunter]

I think I love you. No. Seriously. You are my math hero.

[pwngo]

Also, I find it funny that part of the creative commons says "No Derivative Works"

heehee, math humor

[pwngo]

I'm just picking and choosing amongst the things that were unclear to me in Calc; What video is it where he explains what dx is? My teacher only taught us the "mechanical" way to do equations like he referenced in the last video.

[vanmojo23]

@pwngo I'm not sure he really explains what dx is. But basically dx is the infinitely small change in x. That's the reason why the derivative is written as dy/dx. It's the infinitely small change in y over the infinitely small change in x.

[cowcrusher]

I love these vids but they disable iPad playback!!

[Josh1billion]

Great stuff. This is the one and only section of Calculus that's really been throwing me off this semester, but I've finally been able to visualize the concept thanks to your videos. Many thanks!

[thealmassi1]

you should take a profession in teaching. seriously. You're one of the best (if not the best) tutor/teacher I've EVER had.... And i've never even met you!

[Rainbow2835]

u really helped me a lot!~  much much much of thx

[MagiKpeople]

This is probably my favorite part of calculus!

[lilshortypie72]

"i've been a little rusty since i last did some antiderivatives"

sal? rusty? hoohooohhohooohahahaa

[martmelee]

dude, you are AWESOME!! i understand you even more than my teacher in college and my native language is Spanish. Imagine how good you are if i can understand YOU better.

[dawodchatha]

at 5:40, the antiderivative is pi times ****X*** times x^2 / 2

[holdintightlettngo]

@dawodchatha I think you are mistaken...wouldn't pi be considered the coefficient of x and so just carry over? If it were the antiderivative of pi PLUS x, then you would be right.

[MultiAxian]

the way i remember the volume formula is to remember that the volume is equal to the definite integral of the cross-sectional area of the solid.

[johammbass]

Legend!

[Arrygoo]

this was boring wtf

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I'm just joking you are extremely helpful >:D< thank you for this you really explained it so clearly.

[miestykid]

I was taking a midterm and I accidently put Khan under my "Professor's Name:"....

Oops

[Sylvanas17]

@miestykid lol ur epic

[mattymm34735]

this is so much better than any math textbook or dry step by step guide ive ever read showing how to solve thse questions. If only every math class had a lecture set of videos describing their concepts rather than boring chapters in a textbook i think a lot more people would understand math in general. thank you very much for these videos

[thinkgreenlovepurple]

thanks so much again!

I just can't express how awesome these videos are...

I've never truly understood this until now, I've been relying on my formula book the whole time- which is bad.... haha.

[uralegend987]

Dear Santa

[swatantrakumar2]

man of great understanding

[Shadowpsych990]

thank you thank you thank you...i cant understand my teacher...thanks so much for saving my butt

[dlb8908]

I wish u were my teacher. I have sat and worried and fussed and hollered at everyone and couldnt figure it out. You made it so easy. Thanks man. Ur the greatest.

[JohnNumberThree]

Lol! At 5:17 he draws a frown face!! ------> :( Also, THANKS SO MUCH SAL!!! All of your videos rock! So much simpler than my calc professor.

[CurlyVogel]

cubic units!! :O YOU FORGOT THE UNITZ

[mikej02]

your work is MUCH appreciated mr. khan, im not strong at calc, and any success i've come across is from your help. thank you so much

[ideas4future]

This is helpful

[righteousgroove]

Thank you so much!

[redpillorbluepill]

thank you for everything

[megaelliott]

pi=3.1415926535897932384626433­8327950288419716939937510

[veteran25]

Are you Mr. Khan talking in the video?

[BigPurple121]

WTF! I've been slaving over sloppy lecture notes trying to grasp this EXTREMELY SIMPLE! concept.

Thank you Sal for saving my butt once again.

[woodenjaw]

Welcome to the club!

[navhap]

I have never seen such an intuitive teacher (tutor) in my whole life. YOU ARE Amazing!!

[angelx0515]

LOL "sideways looking cup thing." You're awesome... lol I love how you're semi-perfectionist with this even tho it's a simple drawing program hehe

[musicruleshr]

lame o left us hangin

[bubblegumrissa]

thanks so much! i understand now!

[reets326]

67pi / 6

[alooghee]

im sorry i lost you at 6:37. how is that the equation of a circle? i never knew that

[Invisus944]

No offense, but you shouldn't be learning calculus if you don't even know the equation for a circle. You should have learned that in math class by now.

[alooghee]

yeah well lets just say my school doesnt really care about derivations, just rote learning equations

[SwiperNoSwiping19]

No offense, but I was raised by wolves and I actually discovered the equation for a circle without any human contact by age 9. You should have learned that in math class by now.

[Invisus944]

Huh? What are you saying Swiper.

[dodgersandstorm]

people forget, lawya

[porkman385]

3:51 lol I think you made up a word.

[Invisus944]

No, infinitesimally is a word.

[herrplanck]

what dont you use a civilized software to draw & write stuff? quite useful by the way

[brco2003]

Was there a video posted that calculates the surface area of such solids?

[knowledgeis4me]

same principal except you integrate the formula for surface area instead of area

[darkfighte]

awesome vid yet again