Gradient and directional derivative | MIT 18.02SC Multivariable Calculus, Fall 2010

[@fanglinwang2777]

The speaker explains the concepts in a very logical and clear way. It helps me to understand the material better. Thank you so much.

[@ThatBoyDunn19]

Thumbs up if you're college Calc 3 professor spends too much time on THEORY and DEFINITIONS and not enough time on examples and simple logic of the problems! Nothing like a good KZbin tutorial refresher before your Friday quiz haha! Thank you Joel you da mannnnn

[@Newbport849]

+ThatBoyDunn AMEN

[@NobodiesOfficial]

*your No wonder why you need this sort of content.

[@rondemiller5769]

@@NobodiesOfficial Funny you should correct him as you have spelled it wrong also. Correct spelling is "you're" which stands for you are, lol. "Your" is possessive. When being an ass goes wrong...

[@ganeshr3493]

pussy

[@mianqasim4016]

You commented five years ago and today is Friday and I have my quiz. What a coincidence..😂

[@jpr422]

I think I would totally enjoy sitting in on one of his classes. Listening to him is almost humorous, but yet, he is able to get his point across clearly so you can understand the subject being discussed. He is not one of these instructors with a monotone voice that lulls you to sleep, but is able to keep your attention. Well done, Joel.

[@seacaptain72]

holy shit, i've been trying to get this for a week now. You're seriously the man. I wish you taught here.

[@haydenvanhoose4365]

I learned more in this 13 minutes than I did in my hour and 15 minute lecture over the material, homework, quiz, and studying combined. You made it simple. Thank you!

[@nathandaniel5451]

This guy is so nice to listen to, he's clear, consice and just has a nice voice and 'personality'.

[@hoatrinh2201]

Thanks a lot. You save a lot of people Joel.

[@standish250]

He explains fairly clearly how it works. The gradient isn't some magical visual to mathematics, it tells you the rate of change for a particular function. If you are given a point with coordinates (x,y,z), then you can find the actual values for that particular point given the function, and with the directional vector, calculate the direction. Look to electromagnetism theory if you want applications of the math (Stokes Theorem, Curl, Divergence, etc)

[@willashland4597]

Wow you make this so simple. I took Calc 3 over a year ago and after watching problem 1 I did problem two in less than three minutes... thank you!

[@abcdef2069]

let x^2 + y^2 + z^2 = 1, so that z = f(x,y) z = ( 1 - x ^2 + y ^2 ) ^ (1/2) z < 0 = - ( 1 - x ^2 + y ^2 ) ^ (1/2) z > 0 for z=0, use anything to make it continuous 1. prove the max value of gradient at (x,y,z) = (0,0,1) when the initial point is from (x,y,z) = (0,0,-1) 2. find the gradient at (x,y,z) = (1, 0, 0) from the problem1 , when the gradient becomes infinity

[@LAnonHubbard]

I was a sketchy on this after watching the main lecture. This practice helped me out, thanks. One thing I never really understood from the main lecture was about it being unit speed and arclength.

[@mianqasim4016]

Superb. No problem understanding. Highly simplified the mathematics. Respect 🙌

[@Newbport849]

Who got -1 for C)

[@SuperMushroom85]

This guy is so helpful. 13:34 video=1hour lecture.

[@standish250]

Oh, and it's not a memorization of equations! Del is a definition: (d/dx, d/dy, d/dz) (partial derivatives of x, y, z respectively). So don't say it's just understanding the memorization of equations; go read the book, do a bit of research online and you'll understand what this man has so graciously put online.

[@Pooh0Bear8]

Thank You, MIT for these videos; they are life savers :)

[@powertube5671]

Very well done! For me, this is the best of four videos I've watched on this subject. Bravo!

[@Vince11711]

So helpful. Explained the relationship between vectors and gradients and also made me understand where the formula for these comes from. thanks man

[@MrFilipeGB]

This is an exercise to practice, not a theoretical explanation. As he said in the beginning of the video you were supposed to know what gradient and directional derivatives are before watching this. Try the link below , it shows you the intuiton of gradients pretty well. About directional derivatives I didn't find any. Good luck /watch?feature=player_embedded&v=U7HQ_G_N6vo

[@adrias818]

Superb explanation. Thanks MIT!

[@GREJFilmsLtd]

Fantastic! This was the PERFECT follow up for my students after my directional derivative lecture. Thank you!!!!

[@WhO0P4]

Got it back today, i got a 86%, which is an A in my class because there is a 5% curve. Means that 85%> is an A. 75-85 is a B etc. I'm happy :)

[@thelebaron91]

Great job! very well explained and all done in one take. Impressive!

[@revolvermaster2]

thank you * 1,000,000. Needed this for my economics midterm.

[@Aelfraed26]

Very nice! Also note: Gordon Freeman is a graduate of MIT!

[@belletbinu3614]

I cant understand the idea of gradient in a vector field. Can you explain

[@BalwantSingh-nk1ss]

You sir have saved my ass for my calculus exam next week :)

[@BexHM07]

Best explanation so far!

[@khaledqaraman]

So clear ... Thanks

[@ciltire420]

thanks dear teacher u did my home work really good teacher i loved ur calm and easy clear] explanation

[@ashvithakannan123]

i like the bit when he walks away, and walks back onto the screen. its funny if you watch it without pausing the video when he tells you to pause it xD

[@imegatrone]

I Really Like The Video Gradient and directional derivative From Your

[@PeterJ2k11]

Great video thanks, I just having issues understand why we want the unit vector v, rather than just the plain old vector ?

[@MarioFrustration11]

I came here hoping I would see how gradients and directional derivatives look like and how it really works. this doesnt test the understanding of the knowledge; it tests the understanding of the memorization of equations.

[@MDox94]

thank you very much .... but there is something I didn't get when you take the unit vector and didn't take the vector V ... and what is the different between the unit vector and the vector v ? thanks a lot

[@MassDynamic]

saved many people from certain doom ^_^

[@schrodingerscat3912]

beautiful. excellent work

[@indiaonly9285]

Thank you Guru ji

[@aruqyz]

Thank you!! Thanks to you I understood this topic!!

[@ProfessionalDesi]

from where you take value of 5 in A part at 3/5 4/5

[@DownToTruck]

the magnitude of the vector is sqrt(3^2 + 4^2) or sqrt(25)=5. He just remembered the Pythagorean identity that a right triangle with sides 3 and 4 has a hypotenuse 5 (which is derived in the same way as computing the magnitude of )

[@HDitzzDH]

Is it necessary to use the unit vector to dot with the gradient, can't you just use the vector as it's given?

[@nchristianzevallos7483]

Thank you, very clear

[@bobkameron]

excellent video man!

[@explorador26]

Wow "estudiando" en el MIT!!!

[@mikedelisca]

this dude is a beast

[@hollisterrgurl90]

I love this guy

[@Hippoman141]

@roberth214 there is no way I am insecure, Im flipping excited

[@aradhyamohapatra9413]

Very helpful lecture...

[@andys2972]

Very helpful, thanks

[@abikso2]

nice example...thanks

[@binhtruongquoc2720]

Thank you so much

[@MI-yg9sw]

sir could you explain the gradient h again..

[@petemotz48]

Thank you

[@jmitsc]

at 3:36 what is the meaning of "ds", he wrote df/ds. Shouldn't this be df/dz??

[@SadakoUsagi]

s stands for distance. it's explained in the lecture

[@rohanpatil8919]

thnk u sooo damnn muchhhh!!!!!!!!!! u r truly an aweome speaker got everything u said thank u sooo damn much

[@paktoday4847]

thankyou . sucha a great explanation . keep the good work up 💓

[@Hippoman141]

im taking this class next year (im a sophomore in highschool in calc bc)

[@roni8873]

very well explained :) Thank you.

[@ricorico33]

Nice job man.

[@charan775]

Amazing... No need to watch lecture

[@jetonmejzini7920]

myself awa hjbsmwianhbwkw

[@superguid09]

thankyou from guido and dorian!!

[@saddiqahmad7695]

Thanks

[@standowner6979]

Where can I find tougher problems?

[@mitocw]

The course materials are on MIT OpenCourseWare at: ocw.mit.edu/18-02SCF10. Best wishes on your studies!

[@standowner6979]

@@mitocw Thanks, you're the best!

[@Agouti]

How did your test go?

[@Juciyblueberry]

man that's a very long green board :O

[@shawnkhoo1949]

best tutor

[@eolvra]

JOEL U DA MAN

[@Pooh0Bear8]

when I get these correct the first, I swear it makes me want to run down the street yelling "YYYEEEAAAAHHHHHHHHHHHHH, I KNOW IT!!!!!"

[@stevhg6679]

Tks MÎT

[@Gabriel1443]

Man, you saved my life lol

[@herrzyklon]

but one day, buddy, you will say "Oh yeeeeeahhhh!!"

[@Samsource]

now i feel like im going to MIT but then i get sad because im not.

[@PaulStanley1991]

I'm confused, when you find the gradient of a scalar field do you not find a vector field? ie why don't the gradient values have i,j,k components?

[@Ouranianomicon]

@roberth214 It might even be more hilarious, extending your principle, that you felt the need to call out a sophomore in high school for being insecure. :P

[@WhO0P4]

im fucked for this test on friday

[@SOSA1beast]

haha i hope !!!!

[@redfishgill]

Judging by his name and comment, English isn't exactly his first or second language. Cut him some slack.

[@SOSA1beast]

i in the 7th grade every 5 sec i said huh?

[@JohnSmith-wt9xz]

Who isn't? haha

[@bjjc51192]

LOL

[@kkk3252]

It’s not impressive to watch someone simply plug in numbers after doing some simple operation without any conceptual or overall explanation. He’s horrible.

[@ameerhamza4816]

This was the mit recitation video with lecture. They explained the concept in lecture. Watch lecture

[@TiberusKorel]

i wish he didnt speak with american accent, that accent makes him sound like a clown :P im laughin while im studyin:) in addition thanks for the video

[@kkk3252]

This guy is not very good.

[@randycazales3082]

teach it yourself then

[@NoxuzBlog]

Thank you

[@احمدسلام-د6ت2و]

Thank you