Lagrange multipliers: Extreme values of a function subject to a constraint

[@mariapuff4187]

Never take this video down. You uploaded this when I was in the 5th grade, now I'm a sophomore in university and you explain it perfectly, thank you so much!

[@sapmess]

Perfectly explained! I came here clueless after 2 hours in the textbook and left 7 minutes and 31 seconds later with full understanding

[@JUSTtinaChen]

Instead of paying my professors the tuition money Can I give that money to you? You helped me so much!

[@DrChrisTisdell]

Thanks Imadean! You're right. 5 minutes of video takes about 3-4 hours to film, produce and upload. That's why I try to keep it as simple as possible.

[@nogigglingmajor]

I have always had to work very hard in maths, it is most definitely not my strong point. These help SO much, and you have a very good way of explaining problems. Thanks!

[@ImMajorMongoose]

Thanks Chris!!! Saved me 11 years later.

[@DrChrisTisdell]

That's good to hear. Make sure you study the sample tests that I posted on My eLearning and best of luck with the class test.

[@theallllllknowingggg4367]

At 4:00 can somebody explain how on earth he just comes up with x^2=2y^2

[@DrChrisTisdell]

Thanks very much for your comments and rating. Your feedback is really important and I hope you find the site useful. More videos coming soon. Chris

[@DrChrisTisdell]

@swampwiz Haha! Actually, it is the noise from the air-con units for the building that lie directly outside the window.

[@DrChrisTisdell]

Hi Steve, your suggestion was discussed with a few of the Profs here early this year. It might be an option int he future after a few more videos are posted. .....watch this space!

[@JUSTtinaChen]

I know he is amazing. I've been trying to solve a problem similar to this for like an hour and I was so frustrated until I came here.

[@Nawid101]

You just saved my life Dr. Chris! Thank you!!!

[@DrChrisTisdell]

I'm sure you' ll get the hang of the tute problems with a bit of effort and persistance. Also make sure you look at the sample class tests that I posted on My eLearning.

[@halfdone12]

Thanks Chris, very clear explanation! -ASU Student

[@joycec122]

thanks so much chris! i was stuck on this question for so long and now it seems so easy to do it now in the vid :) i really like ur 2019 lectures :) :)

[@aryankumarprasad1574]

I am in the same boat as you lmao, were you following Thomas' Calculus too?

[@moopoo123]

sweet as. this vid has helps heaps. it seems all good and well when you go through the examples in the 2019 lecture...that is, until I start doing tute problems. Thanks again!

[@DrChrisTisdell]

You're most welcome! : -) By the way - keep working hard, keep thinking in simple terms and I know you'll do great with maths.

[@yoyaya007]

thanks . but how do u know that the two first points r maximun and the two others r minimum with out doing any seconde derivative.....?????

[@yusraalamgire2497]

How do we find out that the point is global extreme or local extreme

[@DrChrisTisdell]

Hi Yoyaya. If you listen carefully, at 6.42 I discuss how to show which points lead to maxima and which points lead to minima. In particular, if you evaluate $f$ at the first two points then you get $1/(2\sqrt{2})$. At the other two points $f$ has value $-1/(2\sqrt{2})$. It is easy to see that the maximum of these set of values is $1/(2\sqrt{2})$ and the minimum value is $-1/(2\sqrt{2})$. Thus, the 2nd-derivative test is not required. Hope I am being clear here and thanks for watching!

[@Descott88]

Thanks for the explanation, I was stuck on the question and this cleared it all up.

[@fartx211]

i get all these Lagrange stuff now. I reckon Math2019 has been pretty good so far.

[@yunikmodi1365]

Very nice way to understand the langrange 's method

[@jramierez3]

Hello chris, Im stuck on a extreme value problem with constraints. Can I email you and can you send me some feed back on that problem?

[@DrChrisTisdell]

Hey, "no worries" as us Aussies say. Happy to help!

[@DrChrisTisdell]

Haha! Lovely idea!! But seriously, if you want to show your support then you can always download my new ebook. The free download link is in the description.

[@DrChrisTisdell]

Thanks again Joyce!!

[@DrChrisTisdell]

Hey, happy to help!

[@yoyaya007]

oh yeah !!! thank u DrChrisTisdell it's very clear!

[@appuz9876]

Thank you sir

[@DrChrisTisdell]

Great!! Thanks!

[@swampwiz]

The hum in the background sounds like a UFO is ready to land.

[@ulivaldo]

Perfect!!! Thanks a lot

[@simranpreetkaur6761]

Watching in 2021😊

[@DrChrisTisdell]

Hahaha!!! So much for my Aussie-French accent??!! :-)