if x+y=8, find the max of x^y (Lambert W function)

  Рет қаралды 747,321

blackpenredpen

blackpenredpen

Күн бұрын

Пікірлер: 812
@blackpenredpen
@blackpenredpen 10 ай бұрын
all solutions to 2^x-3x-1=0 (transcendental equation) kzbin.info/www/bejne/fXvFq6ajmMh5qtk
@pokemonjourneysfan5925
@pokemonjourneysfan5925 10 ай бұрын
Bprp, I have one more question. You know how we solved this problem of maximizing x^y w/ x+y=8 using derivatives? Suppose we restricted the domain of x,y to be natural numbers again. Could we then use discrete calculus to solve this problem. That is forward difference/backward differences are now analogies to the first derivative?
@jonathanv.hoffmann3089
@jonathanv.hoffmann3089 10 ай бұрын
🎉🎉🎉
@rpocc
@rpocc 10 ай бұрын
The finest value of X I’ve found is 3.53540103 but I have no clue how to express the limit of x.
@거북선-b1k
@거북선-b1k 8 ай бұрын
I think the essence of this problem is to get an approximation without a calculator. The video never got to it at all.
@cabbycabbycabbycabbycabby
@cabbycabbycabbycabbycabby 7 ай бұрын
(-4)¹⁶=16,777,216
@farhansadik5423
@farhansadik5423 10 ай бұрын
I literally thought I was glitching with how many times I heard him say 'I really like this question" lmao
@nrxtfwd
@nrxtfwd 10 ай бұрын
Yeah, I really like this question
@geraldpujaya6682
@geraldpujaya6682 10 ай бұрын
he really likes the question
@jamescollier3
@jamescollier3 10 ай бұрын
7:56 you are
@rodrigoappendino
@rodrigoappendino 10 ай бұрын
I thought he was glitching.
@EgzoDiuse
@EgzoDiuse 10 ай бұрын
i wonder if he likes the question
@hysterixation
@hysterixation 10 ай бұрын
"I really love this question, let's... I really love this question, let's have a look. I really love this question, let's have a look." - blackpenredpen
@codycast
@codycast 8 ай бұрын
It’s a dude that holds a little lapel mic. I don’t think he’s too concerned with edit quality.
@giacomocasartelli5503
@giacomocasartelli5503 8 ай бұрын
I don't know about editing, but I think he really loves this question
@the_pks_
@the_pks_ 7 ай бұрын
where are his other videos with that start lol
@Dibbat
@Dibbat 6 ай бұрын
I love this question too!
@CCheukKa
@CCheukKa 6 ай бұрын
He really loves this question
@ZoXiL-X2
@ZoXiL-X2 10 ай бұрын
lambert W function be like : input→fishy fish output→fish
@Friendly-Neighborhood-Asexual
@Friendly-Neighborhood-Asexual 9 ай бұрын
😂😂😂
@mayankdave9739
@mayankdave9739 8 ай бұрын
I see what you did there
@Nico2718_
@Nico2718_ 7 ай бұрын
More like fish*e^fish 😂
@electricgamer_yt4753
@electricgamer_yt4753 6 ай бұрын
BPRP’s ‘lil fish drawings are so cute. Fish*e^fish return fish for life.
@danigarcia2294
@danigarcia2294 4 ай бұрын
lambert w function: defishifier
@SabertoothDeathmouse
@SabertoothDeathmouse 10 ай бұрын
While most of this went completely over my head, it was a fun watch, and I am quite proud of myself that my first thoughts were "Are they positive numbers, and are they whole numbers?"
@sfglim5341
@sfglim5341 10 ай бұрын
The 2 most important parts of the video is recognizing that you have to take the derivative to find the min and max and then realizing that u can use the Lambert W function, everything else is following up on those 2 things
@jack002tuber
@jack002tuber 10 ай бұрын
@@sfglim5341 I understood it all till we hit that lambert W thing. I have never seen it before
@jay-5061
@jay-5061 9 ай бұрын
​@@jack002tuberits a very handy tool in college/uni algebra and calculus.
@HienNguyen-cs1md
@HienNguyen-cs1md 9 ай бұрын
@@jack002tuber It's just a function, you don't need to delve into it too much
@battle00333
@battle00333 10 ай бұрын
At the very start for (-4)^12 it is the same as (-2)^24, for anyone wondering just how much bigger it is.
@xlr8_bs514
@xlr8_bs514 10 ай бұрын
Isn't that common sense lol
@michaelleue7594
@michaelleue7594 10 ай бұрын
Or more directly, (1024)^2.4.
@trueriver1950
@trueriver1950 10 ай бұрын
Which is slightly more than 16 million, because 2⁴ = 16, and 2²⁰ is 1024² > 1,000² So yeah, I'm not arguing with "bigger" 😉
@nunosantos4217
@nunosantos4217 10 ай бұрын
for a lot of people the concept of powers might not be that clear or straightforward. Younger students who may have an interest comes to mind. Of course however, most high-schoolers or college level students (who take math courses), will see it very clearly.@@xlr8_bs514
@brahmbandyopadhyay
@brahmbandyopadhyay 10 ай бұрын
​@@xlr8_bs514ikr
@frostiifae
@frostiifae 9 ай бұрын
found this channel last night. i used to "teach"/tutor math in college and have always been passionate about teaching despite not being very good at it, so I love watching you explain intermediate math in very straightforward ways. but, i personally tapped out of math education in late calculus and linear algebra, and to see a video on more advanced subjects that I'M not even familiar with like the Lambert W... it made me feel very warm and cozy. This is a wonderful channel and I'm delighted to have found it.
@vascomanteigas9433
@vascomanteigas9433 10 ай бұрын
Using Lagrange multipliers should solve the problem. x=1/lambert_w(1) and y=8-1/lambert_w(1)
@subjekt5577
@subjekt5577 8 ай бұрын
for the ignorant, forgetful, and lazy like myself: en.wikipedia.org/wiki/Lagrange_multiplier
@bleaks218
@bleaks218 7 ай бұрын
Using the Lagrange multiplier will give a system of equations identical to solving using the methods of single-variable calculus, ie the solution x+xln(x)=8.
@keaganlove1478
@keaganlove1478 6 ай бұрын
I thought of this method too!
@la.zanmal.
@la.zanmal. 10 ай бұрын
See, the mistake at the end is that you asked ChatGPT 3.5, you should have asked ChatGPT 8/W(8e).
@elimondingwiza3168
@elimondingwiza3168 9 ай бұрын
Elite comment. Simply beautiful
@joshavery
@joshavery 6 ай бұрын
Underrated comment
@anonymouschessaccount5508
@anonymouschessaccount5508 5 ай бұрын
W COMMENT THIS DESERVES TO BE POPULAR THE creativity omg
@anonymouschessaccount5508
@anonymouschessaccount5508 5 ай бұрын
🎉
@GoofyGangster-official
@GoofyGangster-official 5 ай бұрын
This is so underrated
@mike1024.
@mike1024. 10 ай бұрын
This channel has helped me see the usefulness of the product log in some obscure situations, but it comes up frequently enough to remember it.
@atriyakoller136
@atriyakoller136 10 ай бұрын
As a non-mathematician I understood nothing but the way you explain is so cool that it made me more enthusiastic for maths😊
@FourOneNineOneFourOne
@FourOneNineOneFourOne 10 ай бұрын
as non-mathematician you should still know highschool maths, unless you're still in school, then I guess you'll still learn about this.
@atriyakoller136
@atriyakoller136 10 ай бұрын
@@FourOneNineOneFourOne I did learn some of it in high school and even at university, but I graduated from university 5 years ago, my maths class had finished 2-3 years prior, and I have been working in a completely unrelated area. And in my life the only areas of maths I use are arithmetics and trigonometry 😂 so, the other things get forgotten easily. I think we didn't reach this difficulty of calculus at high school, or, if we did, it's gone from my memory, because I understood about half of the video at most. I don't remember any of the functions, sadly.
@apljack
@apljack 10 ай бұрын
@@FourOneNineOneFourOne At least in my case, Calc wasn't even offered unless you qualified to do College Courses while still in Highschool. I got through Calc 1 just fine, but most of what he was showing here is not stuff we really covered. This is the first time I ever heard of W(xe^x)=x, and I would have literally no idea how to parse something like that in a casual way. While I have worked with Log/ln/e a bit back then, it's been over a decade, and I was never fond of dealing with those at all, so I just lost it completely.
@JonesyTerp1
@JonesyTerp1 10 ай бұрын
@@FourOneNineOneFourOne What if one has no aptitude for math? As a high school student, or today more than 30 years later, I could no more understand what he is explaining then I could run 400m in 48 seconds (I never broke the 50s barrier 50.7, and only passed algebra as a senior.) The ability to do high school math, beyond basic algebra, is a mental gift, and is no different than the ability to any number of other things. And no amount of hard work in the world will overcome a lack of ability. If you can do this stuff, congrats to you, but no one “should” be able to do anything you can do.
@GFlCh
@GFlCh 8 ай бұрын
@@JonesyTerp1 "no amount of hard work in the world will overcome a lack of ability". I'm not sure I agree, particularly for all the activities you mentioned, but, putting that aside... The problem is, even if you have the "innate ability", for most (many?) things, you still have to do the "hard work" before you are proficient enough to be convinced you have the ability. So, to find out if you have the ability to do "a thing", you have to take a leap of faith and put in the hard work to find out. One would hope you enjoy "the thing" so if it turns out you can't do it, at least you had fun trying. It comes down to the point, does the hard work "develop" the aptitude, or does it "expose" it? I think there are some people in each group, along with a group who work hard and still can't, and another group who never seriously try.
@meurdesoifphilippe5405
@meurdesoifphilippe5405 10 ай бұрын
I did not notice that x and y should be nonnegative, else you could have (-2k)^{8+2k} which goes to infinity.
@Enlightenment0172
@Enlightenment0172 10 ай бұрын
(even -ωₙ)^(even ωₙ+8) where n is arbitrary Because a negative when exponentiated to a positive even is positive, this produces a value greater than ωₙ₂ Where n⇐∞, the maximum approaches Ω.
@OnlyTheQuack
@OnlyTheQuack 10 ай бұрын
​@@Enlightenment0172!??
@TheSkullkid16
@TheSkullkid16 10 ай бұрын
I mean, if you had it so X could be negative, the max is theoretically infinity, but that min is theoretically negative infinity, which makes the question irrelevant. Knowing that is actually why I clicked on the video in the first place.
@jakeklic
@jakeklic 10 ай бұрын
I was thinking just that!
@AzureKyle
@AzureKyle 10 ай бұрын
@@TheSkullkid16 Exactly. You end up with an equation of -(n-8)+n=8 and then have (-(n-8))^n. The limit would basically be negative infinity to the power of infinity plus 8.
@adammizaushev
@adammizaushev 10 ай бұрын
Considering x >= 0, y >= 0 on my own, I got stuck with x(ln(x) + 1) = 8 Thank you for introducing the W function
@TomJones-tx7pb
@TomJones-tx7pb 7 ай бұрын
yeah but you already had a function, so rephrasing it as another function is not really solving anything.
@adammizaushev
@adammizaushev 7 ай бұрын
@@TomJones-tx7pb but what I stopped with is an implicit function. Explicit solution presents the way to directly calculate the value for a given argument rather than to bruteforce it
@nilsb.4906
@nilsb.4906 4 ай бұрын
Same for me. I also solved the problem before watching the video and got stuck with x ln(x) + x = 8 but I just type it into Wolframalpha and see that it has no "nice solution". In my opinion, there is no benefit in expressing this equation with the W function. The equation x ln(x) + x = 8 can already easily be solved by a computer and for a human the W function does not give you any additional information
@TomJones-tx7pb
@TomJones-tx7pb 4 ай бұрын
@@adammizaushev Good point for classical math, if you have a pre-calculated W function, but modern way of solving is using a computer to get as accurate an answer as you desire with numerical analysis.
@adammizaushev
@adammizaushev 4 ай бұрын
@@TomJones-tx7pb Yeah, I was only speaking in the matter of getting intuitive, natural understanding of a function to a human, which is got by its explicit expression, rather than implicit one
@marusiaskrynnyk7489
@marusiaskrynnyk7489 Ай бұрын
honestly, I understood everything you said (despite this being the first time I've heard about lambert w function) and this made me so happy (also, the fish you draw are amazing)
@wouterellenbroek3411
@wouterellenbroek3411 6 ай бұрын
Great explanation. But what's up with your fish having eyebrows?
@ambiverter
@ambiverter 3 ай бұрын
Fishes also deserve to have personality 😢
@marusiaskrynnyk7489
@marusiaskrynnyk7489 Ай бұрын
these are the most mischievous fish i've ever seen
@herardpique7302
@herardpique7302 10 ай бұрын
The most fascinating about this, is if you do this with X + Y = 100, the maximum will be 24^76, which is totally asymmetrical
@frimi8593
@frimi8593 10 ай бұрын
You mean to tell me that e^{W(100e)-1} is equal to 24?
@abrahamholleran4162
@abrahamholleran4162 10 ай бұрын
Close - the x is still e^(productlog(100e)-1) or 23.947
@frimi8593
@frimi8593 10 ай бұрын
@@abrahamholleran4162 so like, you get that my skepticism came exclusively from the idea that e^{W(100e)-1} is a natural number right? Like, sqrt(2) is "close" to 1.4, but the fact that it's irrational is kind of a really important thing about it
@gregorymorse8423
@gregorymorse8423 9 ай бұрын
W(e)=1 so it's a shame there aren't identities for cases a constant precedes e.
@vez3834
@vez3834 8 ай бұрын
​@@frimi8593 They weren't replying to you, but rather to the original comment. I'm sure they would assume that you were doubting it being an integer. (It can be difficult to tell what people mean, since some use the word "equals" too loosely. You could say something like "exactly 24" or just explicitly doubt it being an integer.)
@jarikosonen4079
@jarikosonen4079 Ай бұрын
10:03 Keep in mind rationalizing the denominator. That case is not needed to put W() in the denominator.
@electricnezumi
@electricnezumi 10 ай бұрын
I often find your videos a bit beyond my skill level but I found this one really approachable and fun. thanks for this!
@Shankster49
@Shankster49 10 ай бұрын
yeah this guy is using calc 1 and maybe calc 2
@nurajannattaslima9853
@nurajannattaslima9853 10 ай бұрын
pretty straight forward
@UENShanix
@UENShanix 10 ай бұрын
This is a great video and you are a wonderful mathematical communicator! Thank you for creating this!
@neilmorrone691
@neilmorrone691 10 ай бұрын
Exceptional explanation of the unique "W" Function! However, I still need to exponentially repeat your Steps to the Solution (or repeat the Steps to the maximum number allowed) --- in keeping with the ultimate objective of this proposal (computing the maximum)! Alas, I am exhausted from this exhilarating mathematical exercise. Bravo! Thank you, sir blackpenredpen!
@bigmiraclewhips
@bigmiraclewhips 7 ай бұрын
didnt understand a word of this but i am now holding a W and a bunch of fish
@bananasplitd006a5
@bananasplitd006a5 7 ай бұрын
I'm happy to say that this is the first problem from your videos that I have been able to solve !🎉
@ronbannon
@ronbannon 10 ай бұрын
Nice problem. Here's the Sagemath code (using Newton's method): sage: reset() sage: f(x)=x^(8-x) sage: g(x)=diff(f(x),x) sage: n(x)=x-g(x)/diff(g(x),x) sage: x=4.0 sage: x=n(x);x 3.35700838162158 sage: x=n(x);x 3.53287101659463 sage: x=n(x);x 3.53539951720032 sage: x=n(x);x 3.53540103555960 sage: x=n(x);x 3.53540103556015 sage: x=n(x);x 3.53540103556015 sage: f(x) 280.904556712676 Note: I picked 4.0 as the starting value because it is between 0 and 8.
@trueriver1950
@trueriver1950 10 ай бұрын
Yes, x=0 is a local minimum because to the left the value of P is unbounded. That means that I think the result we found is not a global max but a local max. Wolfram is mistaken 😮 because it calls it a global max. Or have we told Wolfram that x>=0 ?😊
@carryingautoclicks7501
@carryingautoclicks7501 10 ай бұрын
Wolfram alpha probably ignores negatives entirely here because any noninteger negative x can't be raised to the power 8-x when restricted to the reals.
@KenFullman
@KenFullman 10 ай бұрын
As soon as I saw the question I noticed there's no upper limit because we can have absurdly large negative numbers for X (or Y). Once he put the constraint in that they had to be positive values, I was sure the answer was x=y=4. I just assumed the answer was going to be integers. Don't know why I fell into that trap, it just felt intuitive.
@AzureKyle
@AzureKyle 10 ай бұрын
@@KenFullman Exactly, I was thinking the same thing. Because, you can have the equation as such: y=n, and x= -(n-8) For example, you could have y=1,000,008. x would then equal -1,000,000 and the answer would still equal 8, and you'd be left with -(1,000,000)^1,000,008 which would be absolutely huge, and can still get bigger, into infinity. Because you'd have -(n-8)+n=8 and then (-(n-8))^n. As long as you can have y be 8 more than a negative value of x, you can get infinitely higher values for x and y.
@Tzizenorec
@Tzizenorec 10 ай бұрын
@@KenFullman If the equation had been x*y instead of x^y, then that intuition would be correct, and I frequently encounter situations where it's useful to optimize x*y by setting x=y (maybe you do too). So maybe that explains how you fell into that trap. :)
@ripayanami
@ripayanami 8 ай бұрын
It's always about local extremum, cause blackpenredpen used Fermat's theorem that states that *local extrema* in the interior of a domain must occur at points where the derivative equals zero or undefined.
@einargs
@einargs 10 ай бұрын
This is super fun to watch. I had no idea about the W function.
@xavier9577
@xavier9577 5 ай бұрын
I really hate this question, let’s not take a look.
@yesiamrussian
@yesiamrussian 2 күн бұрын
evil blackpenredpen be like:
@thatssokwekwe
@thatssokwekwe 10 ай бұрын
Always fun mentally juggling x^y | x+y = c among the integers; enjoyed seeing the solution for the reals with a refresher on the W function
@savitsios
@savitsios 10 ай бұрын
I'm a computer scientist who hasn't done math in a couple of years, it felt good to get this on my own 😌
@andrewhalyburton5990
@andrewhalyburton5990 5 ай бұрын
This guy really loves this question
@施其均
@施其均 10 ай бұрын
十分感謝老師解答😊😊
@Bv-yl5dg
@Bv-yl5dg 5 ай бұрын
f(x) = x^(8-x) ln(f(x))' = f'(x)/f(x) the max is at f'(x) = 0, and f(x) can't be infinity so the max is at ln(f(x))' = - ln(x) + (8 - x)/x = 0 Ask a computer for an approximation
@CrimsonHexx
@CrimsonHexx 10 ай бұрын
I got pretty far into the question before I eventually got stuck... Of course the Lambert W function was involved lmao, I still dont know how to properly use that thing
@EmpyreanLightASMR
@EmpyreanLightASMR 10 ай бұрын
It's right there on his shirt. (i'm kidding)
@edward_lado
@edward_lado 10 ай бұрын
He might really love this question
@kolirahman8948
@kolirahman8948 Ай бұрын
a^x=a^y+2^z here(a,x,z,y are positive intigre.) now find the sum of all solution (ayz/(x-1)^2.) Please solve this sir..........
@matteo2042
@matteo2042 10 ай бұрын
I really liked your explanation. Even tho I am out of maths for years now, with some thinking I was at least able to understand your steps!
@nguyendcb
@nguyendcb 6 ай бұрын
guys I think he loves this question
@imincent1767
@imincent1767 6 ай бұрын
I think he really likes this question
@SebastianGarcia-qo7wi
@SebastianGarcia-qo7wi 10 ай бұрын
Solved it with Lagrange multipliers. Glad I still remember Calculus III.
@thedigitaluniversity7428
@thedigitaluniversity7428 10 ай бұрын
Please DO NOT let KZbin sabotage your otherwise excellent videos with nested ads. They throw off the viewers' concentration.
@tomasdvorak7307
@tomasdvorak7307 10 ай бұрын
I appreciate that you don't waste time while giving presentation. 👌🏻
@GrandRezero
@GrandRezero 5 ай бұрын
Literally the video I watched before this was a video on the W function on your shirt..
@GrandRezero
@GrandRezero 5 ай бұрын
And now I see why.. this video is also about the function.. algorithm got me
@Qeisama
@Qeisama 10 ай бұрын
I don't know why YT recommended me this and I'm not a science major, but this intrigued me so much lol.
@richatlarge462
@richatlarge462 8 ай бұрын
I went through my YT feed and marked all the politics, sports, pop culture, and crime stories as "not interested", and now finally I'm seeing interesting content like this in my feed. What took me so long?😀
@david4649
@david4649 7 ай бұрын
​@@richatlarge462I get not being interested in pop culture, sports and stuff, but why did you get rid of politics? Politics are highly important. Its what governs us and bad politics will have bad consequences in society and in people's lifes. When people aren't interested in politics, you eventually get leadership like Russia. So please take an interest in it. I'm sure you make use of your right to vote.
@BobChess
@BobChess 10 ай бұрын
I really like this video. I really like this video, let's have a look. I really like this video, let's have a look!
@JaxEntersEvasion
@JaxEntersEvasion 10 ай бұрын
Much more honest than other youtubers who cut every 2 seconds...
@chickens_are_sus6231
@chickens_are_sus6231 5 ай бұрын
I think he really liked that question
@matthewTaylor1990
@matthewTaylor1990 10 ай бұрын
Hmm this video demonstrates the difference in thinking between an engineer and a mathematician. I paused the video when the question was posed, opened excel, used one cell as an input for X, defined another cell as Y by making it 8 - the X cell, then defined a 3rd cell as the X cell to the power of the Y cell. At this point I used the solver function in excel to maximise the value of the 3rd cell by altering the value of the X input cell. Got the answer in less than a minute by brute forcing it 😅. I will admit blackpenredpen's method was more eloquent.
@bertblankenstein3738
@bertblankenstein3738 6 ай бұрын
I'm right there with you. I might have done a column for x, another for 8-x and one more for the function. Range 3-5 with 0.05 increments, maybe refine around the maximum and called it good at 3.51.
@Abhay-jw2om
@Abhay-jw2om 4 ай бұрын
6:13 I didn't understood how did fish e^ fish is fish. And you said it is in calculus 1,but I have not heard of it
@kafureszipuskza3834
@kafureszipuskza3834 10 ай бұрын
amazing explanation.❤
@tobiasruck
@tobiasruck 10 ай бұрын
Brillant explanation, I was able to follow along completely!
@omaanshkaushal3522
@omaanshkaushal3522 5 ай бұрын
Tried solving using desmos. Plotted x+y=8 first. Then plotted x^y = some constant b. The value of b where the two graphs only have one point of intersection is the maximum value of the function, and that came out to be approximately 280.902799
@sumedh-girish
@sumedh-girish 5 ай бұрын
Calling it out, the answer is going to be pi isnt it? Spoiler : It wasn't. But I am an engineer so good enough
@shkabeeenxd9152
@shkabeeenxd9152 8 ай бұрын
he really wanted to make sure we are aware of his appreciation for the question
@makisekuurisuu
@makisekuurisuu 10 ай бұрын
It's out of the scope of ChatGPT's algorithms LMAO
@kingpet
@kingpet 9 ай бұрын
chat gpt just take info from the internet/database and provide an interpretation. if the database doesnt have the answer, chatgpt wont have it. it doesn't "think" on its own. edit: actually it DOES learn, for it's an AI, but it specializes in predicting what the response to your question is base on the database of information it's accessing. But i dont think it can do math.
@maddenbanh8033
@maddenbanh8033 8 ай бұрын
​​@@kingpetunfortunately chatgpt doesn't have the capabilities to do calculus but it might be able to do basic arithmetic, they could integrate something like Wolfram alpha into chatgpt one day
@prismglider5922
@prismglider5922 7 ай бұрын
@@maddenbanh8033chatgpt has emergent problem solving as a result of understanding human language. Gpt-4 is able to use that problem solving to load arithmetic into premade calculators, like programming languages or Wolfram, in order to “solve” calculus and other math problems. It figures out what steps are necessary, and loads those steps into something that can actually get a confident result. Then it takes that result and moves on to the next step
@DrMcFly28
@DrMcFly28 6 ай бұрын
This was fishier than I expected
@otbwwilliams
@otbwwilliams 5 ай бұрын
I don't know, I just have the feeling...but I'm pretty sure he loves the question
@Peter-qv6ke
@Peter-qv6ke 10 ай бұрын
ChatGPT can’t even exceed calculus teacher That’s what I like to see❤
@windowsforvista
@windowsforvista 10 ай бұрын
I never heard of W before, very cool
@Edzward
@Edzward 10 ай бұрын
I have absolutely no ideia why KZbin recommend this video. Everything went WAAAAY over my head!
@紫原美智子
@紫原美智子 9 ай бұрын
Thanks to you I discovered the Lambert W function.
@ricardcalonge4542
@ricardcalonge4542 10 ай бұрын
This is FASCINATING. You are a Master my friend 👏👏👏👏👏👏👏👏
@AmericanLanguage-u6m
@AmericanLanguage-u6m 10 күн бұрын
this was insanely epic, like for real, this was amazing and so fricking cool :>
@cainghorn
@cainghorn 10 ай бұрын
Ahh, Lambert W. I had to use it to solve an optimal control problem for landing a spaceship once.
@gregnixon1296
@gregnixon1296 10 ай бұрын
Make it so, Ensign Cainghorn.
@gaspi91
@gaspi91 10 ай бұрын
That marker switches were smooth 👍
@NagabhushanBaddi
@NagabhushanBaddi 9 ай бұрын
This can also be solved using binary search import math low = 0 high = 8 delta = 1e-6 while abs(high-low) > delta: mid = (low+high)/2 first = math.pow(mid-delta, 8-mid+delta) second = math.pow(mid, 8-mid) third = math.pow(mid+delta, 8-mid-delta) if firstthird: high = mid else: break print(math.pow(low, 8-low))
@SnijtraM
@SnijtraM 8 ай бұрын
A math symbol I didn't know existed: 🐟(e^🐟)
@UpYourArsenal
@UpYourArsenal 10 ай бұрын
The math was easy, you holding two different colored markers with one hand and writing accurately, is what broke my brain
@poket5560
@poket5560 10 ай бұрын
Here wrote a little python script don’t know if this will help max_num = 0; x = 1 y = 7 while (int(x+y) == 8): print(x+y) if (max_num < x**y): max_num = x**y; x+=0.0001 y-=0.0001 print(x+y) print(max_num)
@PatGunn
@PatGunn 10 ай бұрын
I saw the whiteboard and immediately thought along the same lines.
@kemcolian2001
@kemcolian2001 10 ай бұрын
IDK why, but i am obsessed with BPRP's Lambert W function Videos
@sovietwizard1620
@sovietwizard1620 2 ай бұрын
After watching so many of your videos, I could easily find the answer by myself 😂 The lambert w function is like a normal function to me now.
@sigmascrub
@sigmascrub 10 ай бұрын
x+y=8 y=-x+8 Therefore, x^y=x^(-x+8) Take the first derivative and set it equal to zero ... that's as far as I got 😅
@vanshjain3428
@vanshjain3428 10 ай бұрын
Then apply the Newton-Raphson method to solve for x
@CMANIZABALLER
@CMANIZABALLER 13 күн бұрын
@@vanshjain3428 no. The lambert function 🤦🏾‍♂️
@herardpique7302
@herardpique7302 6 ай бұрын
Fun fact: if x+y=2e, the max of x^y is registered when x=y. In all other cases: if x^yy, if x^y>2e, max of x^y is reached when x
@acelm8437
@acelm8437 4 ай бұрын
As others have pointed out, you could use the same method to get x=k/W(k*e) for the max of x^y when x+y=k. The case of k=8 is interesting though, because 4^4 and 3^5 are so close together. We were already pretty close with 3.5^4.5.
@Bethos1247-Arne
@Bethos1247-Arne 10 ай бұрын
"... to the fish power". Adds a smile on that fish. This is wholesome maths, though a bit ... fishy.
@franciscook5819
@franciscook5819 4 ай бұрын
Much the same - I don't know if it is easier - but from the differential... -ln x -1 +8/x = 0 ln x + 1 = 8/x e.x = e^(8/x) e.8 = (8/x)e^(8/x) W(e.8)=2.26282674=8/x x=3.535401 x^(8-x)=280.9045567
@aeschynanthus_sp
@aeschynanthus_sp 8 ай бұрын
About using fish in a function: my maths teached in high school used horse heads similarly!
@kp9k602
@kp9k602 10 ай бұрын
He really loves this question
@ElarshLamichhane
@ElarshLamichhane 4 ай бұрын
that was just another beautiful solution by my fav youtuber.
@petermueller162
@petermueller162 10 ай бұрын
About one quarter of the way through, I realized I was bamboozled into watch another video with W
@blackpenredpen
@blackpenredpen 10 ай бұрын
Hold that W 😃
@Nystika
@Nystika 10 ай бұрын
he really liked that question, he had a look
@nilsb.4906
@nilsb.4906 4 ай бұрын
My approach before watching the video: x^y is not defined for x0. Since x^y < 1 for x>0 and y
@omuploads
@omuploads 10 ай бұрын
I think if you wanted another number other than 8, all you need to do is replace 8 in the solutions with that number so get the answer
@KL-lt8rc
@KL-lt8rc 10 ай бұрын
Instructions unclear. I now have 1,024 fishes.
@sk8rdman
@sk8rdman 10 ай бұрын
I like how he shows that ChatGPT is unable to find the solution at the end. Sure, it can spit out an explanation for how to find the solution, because those sorts of explanations are in its training data, but it can't process the solutions for itself because it doesn't "understand" what the explanation means. It can't create a mathematical model, much less perform the operations to process it, because it has no understanding or procedure for that. It only recognizes that this sort of problem resembles the maxima/minima problems from its training data, and regurgitates a procedure. It's useful to recognize the limitations of the language model.
@NONO-hz4vo
@NONO-hz4vo 10 ай бұрын
I don't pay for v4 but v3.5 has always been awful at calculus and has only gotten worse as they have limited the product. I love learning how to solve problems (hence why I am here) but I have yet to find a good AI solution.
@ugielka
@ugielka 9 ай бұрын
for some reason this specific video plays in picture in picture mode without premium
@boxvism
@boxvism 7 ай бұрын
Thank you,! I wasted some time trying to solve this only with derivates and found only (0, 8) and (8,0) 😞. I don't even remember the Lambert W from school. Very nice!
@Bubafluber
@Bubafluber 10 ай бұрын
Are there solutions if X and Y are complex numbers?
@slovhol
@slovhol 10 ай бұрын
No, because you cannot compare the size of imaginary numbers. You would have to rephrase to find the maximum of |x^y| for instance.
@wiilli4471
@wiilli4471 10 ай бұрын
Complex numbers arent ordered bud
@IoT_
@IoT_ 10 ай бұрын
Another Chatgpt response when I asked it to solve using calculus: Certainly! To solve this problem using calculus, we first express \(y\) in terms of \(x\) using the constraint \(x + y = 8\), which gives us \(y = 8 - x\). Our function to maximize is therefore \(f(x) = x^{8 - x}\). To find the maximum value, we need to: 1. Take the derivative of \(f(x)\) with respect to \(x\). 2. Set this derivative equal to zero and solve for \(x\) to find critical points. 3. Check these critical points to determine which one gives the maximum value of \(f(x)\). The derivative of \(f(x)\) can be challenging because it involves both the power rule and the chain rule. Let's calculate it. from sympy import symbols, diff, solve # Define the symbol x x = symbols('x') # Define the function f(x) = x^(8 - x) f = x ** (8 - x) # Take the derivative of f with respect to x f_prime = diff(f, x) # Find the critical points by solving f'(x) = 0 critical_points = solve(f_prime, x) # Show the derivative and critical points f_prime, critical_points The critical point for maximizing the function \(f(x) = x^{8 - x}\) is \(x = \exp(-1 + \text{LambertW}(8e))\), and the maximum value of \(f(x)\) at this point is approximately 280.905. This result confirms our earlier graphical analysis, demonstrating that calculus provides a precise way to determine the maximum value of \(x^y\) given the constraints \(x, y \geq 0\) and \(x + y = 8\).
@VladimirPutin21172
@VladimirPutin21172 10 ай бұрын
Can you please solve for a b and c the equation 4×a^2+4×b^2+3=4c+4 sqrt of a+b-c . Is for a friend.
@MrFrmartin
@MrFrmartin 9 ай бұрын
He really really really loves this question
@gownerjones
@gownerjones 10 ай бұрын
If you ask GPT-4 instead of GPT-3.5, you get the correct answer. ChatGPT will now write python programs to calculate precise results for questions like these.
@orangee_blox
@orangee_blox 3 ай бұрын
when he started demonstrating functions with fish i thought i was hallucinating
@Reggat
@Reggat 10 ай бұрын
All of this, just to get .2 higher value. But hey! Progress is progress! XD Keep up the content! You've earned a sub!
@RonJohn63
@RonJohn63 8 ай бұрын
Two iterations of Python got me the answer: "for f in [x * .01 for x in range(340,370)]: print(f, f**(8.0-f))"
@grimanium
@grimanium 9 ай бұрын
Quick education on fish or fishes: a fish is one singular fish, the fish are multiple fish from the same species of fish, the fishes are multiple fish from multiple species of fish :)
@qzwxecrv0192837465
@qzwxecrv0192837465 5 ай бұрын
My youngest son hit his high school math teacher with a similar answer as there was no criteria on a range for the problem, as with her and must all be positive.
@SirNobleIZH
@SirNobleIZH 10 ай бұрын
I love how all his fish are evil
@Change_Verification
@Change_Verification 6 ай бұрын
I calculated the derivative in my head and got the following results: X ~= 3.53540103556015 and Y ~= 4,46459896443985. Accordingly X*Y ~= 280,90455671267609. 🙃
@atlaPhanVanat
@atlaPhanVanat 6 ай бұрын
This is the true that i liked satisfaction mathematic problem
@PureHanbali
@PureHanbali 5 ай бұрын
The fish looks like a naughty, annoying infinity 🤣
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