let's solve an impossible integral
An outrageous infinitely nested integral solved using the Lambert W function and some cool tricks.
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• Complex Analysis Lectures
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Пікірлер: 39
Given how often you use them, a mini course on special functions would be most fitting and welcome.
Hi, You can simplify a bit, knowing that g(z+1)=z g(z) , you can write : g(1 -1/n) = -g(-1/n) / n so : I = -g(-1/n) / (n^(1/n)) "terribly sorry about that" : 1:15 , 4:32 , 4:38 , 13:36 , "ok, cool" : 2:05 , 3:35 , 4:30 , 4:38 , 6:12 , 7:36 , 9:45 , 12:09 , 12:56 ,.
No,you will solve this impossible integral,i'l just watch and enjoy😂😊
You should try to generalize the indefinite integral of any inverse function!
why introduce the lambert W function in the first place? we know that ye^y= 1/x^n through this alone we can find dx in terms of dy and then boom you get the same result
@Anonymous-Indian..2003
Ай бұрын
Bhai maine bhi aise hi Kiya, Vichaar milte hamaare 😂 Btw, you JEE aspirant ?
@liamturman
Ай бұрын
Because it’s cool :(, don’t be mean to our cool niche functions, they need to see the light of day sometimes too.
Very nice result. Thanks for solving this monster integral.
For N=2 we obtain a nice closed form sqrt(2 π)
Absolutely beautiful integral
Hey friend 😊. It was easy for me as I solved many such vedios of yours.
@maths_505
Ай бұрын
Always love to hear from you my friend
babe wake up new maths 505 video just dropped
whoa that is SERIOUSLY cool ❤
It's interesting that this is the first integral in your channel where i can actually do it LoL
Ohhh-kei cool!
ze best pre-exam procrastination regime
12:45 If I'm not wrong you forgot to write a factor of N outside the factorisation so technically it should be N ^2-1/N right?
She W on my Lambert til I Function
@stefanalecu9532
Ай бұрын
Lambert W rizz
It would be beautiful for n=2
When I did the problem, I simplified further with Euler's reflection formula. I don't know if it was worth it.
Plz make a problem sheet on integrals
Could you do a video on techniques for nonlinear or just tricky differential equations? I got spoiled by laplace 😭
you get a nice result when N = 2
1:49 i didnt understand the inverse function , is there a video that explain it ?
Is there any easier integrals that involve this type of recursive integral? This is really cool but so much algebraic manipulation and W function
@maths_505
Ай бұрын
Well we don't do easy integrals here quite often. We do really tough ones that teach people new concepts. I encourage you to do further research about the Lambert function. Trust me you'll enjoy it insha'Allah
@BigTonyPersonal
Ай бұрын
@@maths_505 Oh I would gladly do an integral like this, it's just I like challenging my less experienced friends with interesting integrals. Was wondering if you or anyone else had any pretty ones like this that could be doable for someone with around A-Level experience ☺️
Matheamtica didn't get this one. (But you did)
@maths_505
27 күн бұрын
As usual😎😂
What’s the limit as N -> \infty?
@seanshameless0
Ай бұрын
Infinity, it’s just simplifies to N as N approaches infinity
Okkkkkk cooooool
@vladthemagnificent9052
Ай бұрын
terribly sorry about that
=I(W(x^(-n))dx)=???
y=ln(1/(x^N•y))=-ln(x^N•y) e^-y=y•x^N ye^y=x^-N y=W(x^-N) I=int[0,♾️](W(x^-N))dx ye^y=x^-N (y+1)e^y•dy=-N•x^-(N+1)•dx W(x^-N)=y x^-(N+1)=(ye^y)/x x=(ye^y)^-(1/N) I=-sgn(N)•1/N•int[0,♾️](y^-(1/N)•(y+1)e^-(y/N))dy t=y/N Ndt=dy I=-sgn(N)•N^-(1/N)•int[0,♾️](t^-(1/N)•(Nt+1)e^-t)dt I=-sgn(N)•N^(1-1/N)•int[0,♾️](t^(1-1/N)•e^-t)dt-N^-(1/N)•int[0,♾️](t^(-1/N)•e^-t)dt I=-sgn(N)•N^(1-1/N)•gamma(2-1/N)-N^-(1/N)•gamma(1-1/N) I=sgn(N)•((1/N-1)N^(1-1/N)-N^-(1/N))gamma(1-1/N) I=sgn(N)•N^-(1/N)•(1-N-1)•gamma(1-1/N) I=-sgn(N)•N^(1-1/N)•gamma(1-1/N) yay i got one edit: if N is positive, the bounds are [♾️,0]. If N is negative, the bounds are [0,♾️]. If N=0, the bounds are [w,w], where w=W(1) is transcendental, and I becomes 0 because the bounds are the same. Thus, there's a factor of sgn(N).
@maxvangulik1988
Ай бұрын
It wasn't until the end of the video that he stated that N is a positive integer. Still, I think the sgn(N) is p cool