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I Found Out How to Differentiate Factorials! 

BriTheMathGuy
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Have you ever wondered how to find the derivative of a factorial? In this video I'll show you how to differentiate factorial functions! It's time to find out how to differentiate the factorial of x. \
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#math #brithemathguy #factorial
Disclaimer: This video is for entertainment purposes only and should not be considered academic. Though all information is provided in good faith, no warranty of any kind, expressed or implied, is made with regards to the accuracy, validity, reliability, consistency, adequacy, or completeness of this information.

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26 сен 2024

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Комментарии : 482   
@BriTheMathGuy
@BriTheMathGuy Год назад
🎓Become a Math Master With My Intro To Proofs Course! (FREE ON RU-vid) ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-3czgfHULZCs.html
@kennethgee2004
@kennethgee2004 8 месяцев назад
answer is still no. You are taking the derivative of the gamma not factorial. I also do not think that the gamma function is valid as it breaks the rules of factorial and ends up with imaginary numbers in the negative, which actually do exist for all negative values in factorial. It is just the negative side does not go towards anything nice. Derivatives by definition must be on continuous functions. The gamma function is not continuous.
@seroujghazarian6343
@seroujghazarian6343 7 месяцев назад
​@@kennethgee2004nah
@MatesMike
@MatesMike 3 года назад
"That's a good place to start" I undesrtood the reference hahahaha
@banana6108
@banana6108 3 года назад
Me too 😂
@SergioLopez-yu4cu
@SergioLopez-yu4cu 3 года назад
I know you...
@jimjim3979
@jimjim3979 3 года назад
Michael Penn?
@emilioparedesbarba4032
@emilioparedesbarba4032 3 года назад
Qué haces aquí :v
@MatesMike
@MatesMike 3 года назад
@@jimjim3979 yes!
@benyseus6325
@benyseus6325 3 года назад
Take the derivative of floor function. Take derivative of ceiling function. Take derivative of modulo function. Take integral of error function. Take Fourier Transform of Step function (Heaviside). Take integral of e^e^x.
@alexterrieur6858
@alexterrieur6858 3 года назад
For the floor and ceil fonction, derivitives areF:R\Z -> R x |---> 0
@pedrosso0
@pedrosso0 3 года назад
1. 0 for x is not an integer 2. 0 for x isn't an integer 3. Modulo has two variables, you need to specify which one is to be derived 4. x*erf(x)+e^(-x^2)+C by integration by parts It's even in the wiki en.wikipedia.org/wiki/Error_function
@pedrosso0
@pedrosso0 2 года назад
7. is defined with help of the exponential integral. Ei(e^x)
@hassanshaikh3451
@hassanshaikh3451 2 года назад
The first 2 are impossible, they are both defined by not being continuous. If you took the derivative of small sections like between 0 and 1 or something, the derivative would be 0 as they have no "velocity"
@spacebusdriver
@spacebusdriver 2 года назад
@@hassanshaikh3451 it is possible if you use the distributional derivative, but strictly speaking you wouldn't get a function in the normal sense but a distribution which is basically a linear functional on the hilbert space of functions if i remember correctly
@tasneemmidhat6741
@tasneemmidhat6741 3 года назад
I have uncontrollable urge to click on maths videos that intrigue me, and this definitely one of them, very great!
@BriTheMathGuy
@BriTheMathGuy 3 года назад
Wow, thanks!
@hasanjakir360
@hasanjakir360 3 года назад
Derivative turned into integration!!! Unexpectedly awesome.
@BriTheMathGuy
@BriTheMathGuy 3 года назад
Right?!
@Cjnw
@Cjnw 9 месяцев назад
​@@BriTheMathGuythis should be the case, because each component of e^x is based on a reciprocal of a factorial.
@michel_dutch
@michel_dutch 3 года назад
The Gamma function is simply amazing.
@BriTheMathGuy
@BriTheMathGuy 3 года назад
I know right?!
@David-km2ie
@David-km2ie 3 года назад
No
@failurehaus5979
@failurehaus5979 3 года назад
@@David-km2ie based
@ssaamil
@ssaamil Год назад
I love it too much.
@JoaomogusGD51015
@JoaomogusGD51015 Год назад
θ
@Handelsbilanzdefizit
@Handelsbilanzdefizit 3 года назад
What's the inverse of the factorial? Is there a function: f(120) = 5 --> Or generally: f(x) = y where y! = x And how do you invert the gamma-function (in positive 'R')?
@ezequielangelucci1263
@ezequielangelucci1263 3 года назад
gamma doesnt have inverse but the gamma function at 1 to infinity?
@angelmendez-rivera351
@angelmendez-rivera351 3 года назад
You cannot invert the factorial function, since it is not injective, nor is it surjective.
@andrasfogarasi5014
@andrasfogarasi5014 2 года назад
@@angelmendez-rivera351 Well, it does have a right inverse (on the domain of non-zero reals because fuck zero). But not a left inverse, which is the one you're likely referring to.
@angelmendez-rivera351
@angelmendez-rivera351 2 года назад
@@andrasfogarasi5014 The word "inverse" in mathematics typically refers to the two-sided inverse, unless otherwise specified. If you ignore 0, which is arbitrary, then it is surjective, but not injective, so it would have a right-inverse, but not a left-inverse, and therefore, no inverse. For it to have an inverse, or alternatively, to be invertible, it must have both a left-inverse and a right-inverse.
@dafureveerbhadra2772
@dafureveerbhadra2772 2 года назад
@@angelmendez-rivera351 it is bijective in its own domain and range, we want to define it only where x is actually a factorial of something
@BriTheMathGuy
@BriTheMathGuy 3 года назад
What else can you "not" take the derivative of?
@mathevengers1131
@mathevengers1131 3 года назад
How about differentiating super cube root of x?
@mathevengers1131
@mathevengers1131 3 года назад
Can this be integrated? (Φ^(x))-(-Φ)^(-x))/√5 Where Φ is the golden number.
@ydg_me
@ydg_me 3 года назад
Me
@mathevengers1131
@mathevengers1131 3 года назад
x/0
@aashsyed1277
@aashsyed1277 3 года назад
HMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
@garrytalaroc
@garrytalaroc 3 месяца назад
Now to evaluate that horrible looking integral
@mehmet2247
@mehmet2247 3 года назад
I am happy to see that your channel is getting bigger. Soon gonna be 100k, thanks for all videos, greetings.
@BriTheMathGuy
@BriTheMathGuy 3 года назад
Thank you very much!! Really appreciate the support!
@francesco1777
@francesco1777 3 года назад
Little precisation that none will care about: swapping the integral with the derivative requires some hyphothesis. For example the integrand must be continous with continous derivative(and here this is easily verified). Otherwise the step may be incorrect. Good video!
@clementboutaric3952
@clementboutaric3952 3 года назад
you must find a function g such that for all x and t, |f(x,t)| < g(t) with g being integrable over the same domain as f with respect to t.
@BriTheMathGuy
@BriTheMathGuy 3 года назад
Thanks for pointing this out! I tend not to be totally rigorous on RU-vid :)
@clementboutaric3952
@clementboutaric3952 3 года назад
@@BriTheMathGuy As someone else pointed out in another comment, the purpose of your video is not to focus on such tedious details.
@francesco1777
@francesco1777 3 года назад
@@clementboutaric3952 I know that it's not the purpouse of the video, I just thought it would be interesting to provide insights on why this actually works. I think that tediousness is a relative concept, for me they are not tedious details.
@clementboutaric3952
@clementboutaric3952 3 года назад
@@francesco1777 Well once you know that one can not swap however one wants, you can't go back. These details become everything but details.
@lemonteurdesanuseur9686
@lemonteurdesanuseur9686 2 года назад
I actually don’t care about derivating the factorial function, but I knew this was going to be about the gamma function and the demonstration of why it’s a good candidate to extending the factorial to |R really was impressive
@capjus
@capjus 3 года назад
Very interesting (something like that) : With sum of inverse factorial you get e With half factorial squared you can get pi Thats very very interesting for me!!
@paolomorseletto3030
@paolomorseletto3030 3 года назад
How u get pi from half factorial squared?
@capjus
@capjus 3 года назад
@@paolomorseletto3030 pi=4*(1/2)!^2
@guyedwards22
@guyedwards22 3 года назад
The derivatives of the gamma function become extremely self-referential and nested within each other, it's actually really cool! (Look up the digamma and polygamma functions)
@ydg_me
@ydg_me 3 года назад
Not that I understand it but sounds cool 😎
@rosskrt
@rosskrt 2 года назад
I really approciate you explaining everything and not just saying _'trust me bro!'_ . Helps a lot understanding the video at the first watch. Subscribed!
@davidgillies620
@davidgillies620 3 года назад
As a followup it might be nice to introduce the digamma function (or polygamma functions in general). One thing I particularly like is the derivative of the gamma function at integer points which involves the ubiquitous Euler-Mascheroni constant.
@zygoloid
@zygoloid 3 года назад
There are lots of continuous functions that match the factorial function on the integers. The (shifted) gamma function is certainly the most popular one, and indeed in some circles people do use the ! notation to refer to it, but calling this the derivative of the factorial function seems like a stretch.
@radadadadee
@radadadadee 2 года назад
pure clickbait
@nuranichandra2177
@nuranichandra2177 3 года назад
Great approach to an interesting problem. The question is how to address the integral? Is there a follow up video? Thanks
@zetacrucis681
@zetacrucis681 2 года назад
For a little intuition for how fast the factorial function is growing, it's Stirling's approximation to the rescue: ln(x!) ~= x ln(x) - x d(ln(x!))/dx ~= ln(x) dx!/dx ~= x! ln(x)
@nicolasbustos6234
@nicolasbustos6234 8 месяцев назад
Hi, I've been working on a proof myself, and stumbled on to x!, having to differenciate it. I knew about the gamma function and it's derivatives, but I was wondering If whe restricted the x value to be an integer, would the derivative have a non-integral form? I couldn't found anything about it, so I thought maybe with complex analysys use the fact that Gamma is meromorphyc and then have a power series. But then again i trouble myself with calculating the n'th derivative in a certain point (integer) because i couldn't find a non-integer form of an n'th derivative of the gamma function on an integer
@yoavshamariz7362
@yoavshamariz7362 3 года назад
I swear two days ago i looked for video about derived of factorial and found nothing literally nothing so thank u very much for reading my mind
@BriTheMathGuy
@BriTheMathGuy 3 года назад
🤯 You're very welcome!
@griffisme4833
@griffisme4833 3 года назад
ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-kjK9WfmLElo.html
@griffisme4833
@griffisme4833 3 года назад
ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-CcRzJPQzzoI.html
@griffisme4833
@griffisme4833 3 года назад
ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ilOrf8MB5_w.html
@griffisme4833
@griffisme4833 3 года назад
You didn't look very well...
@MrCigarro50
@MrCigarro50 3 года назад
For us statisticians this function is very important. We use this expression thousands of times throughout our careers, but I never thought of the derivative of this function. Very ilustrative, very impressive. Thank you.
@BriTheMathGuy
@BriTheMathGuy 3 года назад
Thanks for sharing and thanks for watching!
@jurimonikalita6068
@jurimonikalita6068 2 года назад
My brain at 3a.m. : let's differentiate factorials XD
@Bodyknock
@Bodyknock 3 года назад
I like the graphics but I realized watching this versus the vids where the formulas are written on the board by hand that this one seems like it’s slightly too fast paced, there’s not enough time to read and really think about the equations as they appear on screen. When they were written by hand it created a naturally slower pace to the script where something would be explained since it took a little more time to write things out. I think the best of both worlds is keep the new graphics, they’re great, but intentionally speak a little more slowly and include some slight pauses to give the viewer time to digest what just appeared.
@BriTheMathGuy
@BriTheMathGuy 3 года назад
I totally agree. This was my first time trying a totally animated video, so I'm still getting the pacing down. I really appreciate the detailed and thoughtful critique! Thank you for watching!
@ДанилоАнтонів
@ДанилоАнтонів 3 года назад
Q: So, what if you differentiate x! ? A: It becomes worse
@damianbla4469
@damianbla4469 3 года назад
03:50 Polynomial (or power function) ("t^x"), natural logarithm ("ln(t)") and expotential function ("e^(-t)") in one place (and all three multiuplied) - amazing! Btw It is interesting what are the results of these questions: 1) d/dx( x^2 * ln(x) * e^x ) = ? 2) ʃ ( x^2 * ln(x) * e^x ) dx = ? 1') d/dx( x^2 * log.2(x) * 2^x ) = ? 2') ʃ ( x^2 * log.2(x) * 2^x ) dx = ?
@namangoyal1297
@namangoyal1297 6 месяцев назад
And we can also write this as a product of the digamma function and the gamma function, since Ψ(z+1)=Γ'(z+1)/Γ(z+1). Thus, d/dx(x!)=x!•Ψ⁰(x+1)
@jaikrishnanp2006
@jaikrishnanp2006 8 месяцев назад
U can substitute y=x! y=x(x-1)(x-2)(x-3).... Taking natural logarithm on both sides lny=lnx(x-1)(x-2)(x-3).... ln(ab)=lna+lnb lny=lnx+ln(x-1)+ln(x-2)+ln(x-3)...... Differentiating on both sides (1/y)dy/dx=1/x +1/x-1 +1/x-2 +1/x-3....... dy/dx=y(1/x +1/x-1 +1/x-2 +1/x-3...) Substituting y we get dy/dx=x!(1/x +1/x-1 +1/x-2 +1/x-3...)
@muratkaradag3703
@muratkaradag3703 3 года назад
I have shown this in 2017 to my theoretical physics prof and her assistent. They once asked if anyone could do the derivative of x!. I said yes and 1 thing is if x is discreet, we can do the log (f(x)) = log(x!) derivative , but in this case there are only integers llowed, and the other way for all x is working with the derivative! Im Glad that someone else did the exact same thing like me! Keep it up friend ! You are awesome!
@zaidsalameh1
@zaidsalameh1 3 года назад
Nice video! Now we need to integrate the factorial (if possible)
@Noam_.Menashe
@Noam_.Menashe 3 года назад
On what bounds? It would be a double integral for X and t.
@romajimamulo
@romajimamulo 3 года назад
Is there a way to then simplify that integral at all?
@angelmendez-rivera351
@angelmendez-rivera351 3 года назад
There is not, not really
@BriTheMathGuy
@BriTheMathGuy 3 года назад
There are probably different representations but as far as I know that's as simply as it gets 😬
@vinayakchawla2510
@vinayakchawla2510 3 года назад
Why not use the pi function?
@rikschaaf
@rikschaaf 9 месяцев назад
Is the Gamma function the only function that satisfies Gamma(x+1) = x*Gamma(x) and Gamma(1) = 1? Or is there a whole group of functions that satisfy this?
@adilcrafts1460
@adilcrafts1460 Год назад
how did you turn a derivative of a factorial to an integral?! This is amazing!
@stinkybohoon71
@stinkybohoon71 8 месяцев назад
It's terrific, thanx, I'll show it to my sonny for the scientific high school math exam preparation
@mathevengers1131
@mathevengers1131 3 года назад
I was waiting for this.
@BriTheMathGuy
@BriTheMathGuy 3 года назад
Hope it was worth the wait!
@mathevengers1131
@mathevengers1131 3 года назад
Yes it was.
@xanderlastname3281
@xanderlastname3281 Год назад
Easy, x! Is also (x^1) * ! So using just your standard power rule, bring the power down, subract one, and then you get 1*(x^0)*! Therefore, d/dx(x!) = !
@SoufianeIdrissi123
@SoufianeIdrissi123 8 месяцев назад
3:19 we can slip the derivative inside in this specific case using a theorem but it's not always true unfortunately
@rexdalit3504
@rexdalit3504 3 года назад
Hi Bri. You have "formally solved" the problem, but I think quite obviously, you have left the hard part, i.e. the integral, unsolved. To use this "solution" in, say, an engineering model, one would actually have to solve it by some method, albeit perhaps approximation. [This is one of the many frustrating aspects of mathematics education.] The video is quite helpful, but I assert, incomplete.
@rennoc6478
@rennoc6478 5 месяцев назад
And someone who’s currently taking ap calc ab right now. I can’t comprehend any of this
@mastershooter64
@mastershooter64 3 года назад
now time to figure out how to take the partial derivative of single variable function
@herbcruz4697
@herbcruz4697 3 года назад
Well, if you had something like f(x)=2x-5 in the single-variable case, we could make this a multivariable equation, instead, if we wanted to (i.e., f(x,y)=2x-5) (This is now a function in terms of both x and y). Then, taking the first-order partial derivatives of this function, we get that ∂f/∂x=2 (The derivative of 2x (with respect to x) is just 2, and the -5 is a constant, so its derivative with respect to anything is just equal to zero (0)) and ∂f/∂y=0 (Here, since we are differentiating with respect to y, we treat x like a constant, but since there are no y's in this function, the whole 2x-5 is treated like a constant, so the partial derivative of this function (2x-5) with respect to y is just equal to zero (0)). We could even go further and make this a function of 3 (i.e., f(x,y,z)=2x-5, in the case of the function being a function of 3 variables) or more variables, if we wanted to, and the first-order partial derivatives with respect to those other variables would also be equal to zero (0), for the exact same reasoning as when we took the (first-order) partial derivative of the above function with respect to y (So, if we had f(x,y,z)=2x-5, then ∂f/∂z=0, etc.).
@mastershooter64
@mastershooter64 3 года назад
@@herbcruz4697 f(x, y) = 2x - 5 f(x) = 2x - 5 f(x, y) = f(x) wait what? did I do something wrong here? how can a multivariable func be single variable at the same time?
@herbcruz4697
@herbcruz4697 3 года назад
@@mastershooter64 It just reduces down to the single-variable case.
@angelmendez-rivera351
@angelmendez-rivera351 3 года назад
The partial derivative of a single variable function is well-defined. We just call it the ordinary derivative, though.
@handschich7736
@handschich7736 3 года назад
I wonder if there are other functions f with this "factorial feature", that f(x) = x*f(x-1), but with other variations. Like you have to shift the Gamma function by -1, that it matches the original factorial values.
@andrewgrebenisan6141
@andrewgrebenisan6141 3 года назад
There are
@handschich7736
@handschich7736 3 года назад
@@andrewgrebenisan6141 Do they have a certain name?
@angelmendez-rivera351
@angelmendez-rivera351 3 года назад
Look at the Pi function. It is defined so that it matches the factorial exactly. In other words, Π(x) = Γ(x + 1).
@TEPK-2924
@TEPK-2924 Год назад
gamma function can also be represented as infininite multiplacation, which is gamma(x)=(1/x) * (product from n=1 to infinity){(1+1/n)^x / (1+x/n)}. since x! = gamma(x+1), x! = (1/(x+1)) * (prod. n=1 to inf){(1+1/n)^(x+1) / (1+(x+1)/n)} Take natural logarithm both side and differentiate to get (x!)'/x! = -1/(x+1) + (sigma n=1 to inf){ln(1+1/n) - 1/(n+x+1)} = lim(b->inf){ln(b+1) - (sigma n=0 to b){1/(n+x+1)}} = lim(b->inf){ln(b+1) - (sigma n=1 to b+1){1/(n+x)}} = lim(b->inf){ln(b+1) - (sigma n=1 to b+1){1/n - 1/n + 1/(n+x)} = lim(b->inf){(ln(b+1) - (sigma n=1 to b+1){1/n}) + (sigma n=1 to b+1){1/n - 1/n+x}} = -γ + H_x ,where γ=0.5772... is euler mascheroni constant (also being a derivative of x! at x=0 times -1), and H_x is harmonic numbers (H_n is 1+1/2+...+1/n for natural n, generalized to real numbers) Thus, (x!)' = x! * (-γ + H_x).
@TEPK-2924
@TEPK-2924 Год назад
For example, for f(x)=x!, f'(3) = 3! * (-0.5772 + 1 + 1/2 + 1/3) = 7.5367...
@Bernhardseckm
@Bernhardseckm Год назад
Derivative of the W-Lambert funktion W(x)
@p_square
@p_square 3 года назад
I was expecting some pi(-ish) thing from this derivative but it isn't. But, as always nice video
@BriTheMathGuy
@BriTheMathGuy 3 года назад
Glad you liked it!
@khanhtran-gw3pm
@khanhtran-gw3pm Год назад
What values of x could you find a value for the indefinite integral at the end? The weird power log exponential product looks like finding an exact answer would be annoying
@o5-1-formerlycalvinlucien60
0:44 should 0! be one? Why is there a vertical asymptote?
@pleasegivemeaciggy
@pleasegivemeaciggy 2 года назад
I still didn't take calculus or higher maths until now, but I still kinda understood. Your explanation is great! I like the idea.
@ianrobinson8518
@ianrobinson8518 2 года назад
By taking logs of both sides of y = x! and differentiating we find y’ = x! (1/x + 1/(x-1) + 1/(x-2) + … ) = x! ψ(x) where ψ(x) is the digamma function, the differential of ln(Γ(x+1))
@vinayakchawla2510
@vinayakchawla2510 3 года назад
Please explain why did you apply by parts integration method to the gamma function? Like why integrate it?
@coursmaths138
@coursmaths138 2 года назад
No. The goal is to prove that the gamma function satisfies the same relation as factorial
@armisol00
@armisol00 8 месяцев назад
why is the limit for x=r and r going to infinity from r^x * e^-r /x =0 ? for x=0 i understand but that i dont understand
@PowerUpStudio_
@PowerUpStudio_ 2 месяца назад
its the gamma function Gamma(z+1)=z! and d/dz Gamma(z) = Gamma(z)Digamma(z) so d/dz z! is technically Gamma(z+1)Digamma(z+1) where Digamma(z)=d/dz(ln(Gamma(z)))=-gamma-sum(n=0,inf)(1/(n+1)-1/(x+n)) where gamma is the Euler-Mascheroni constant
@gamedever
@gamedever Год назад
One can use Stirling's Approximation as well. X! ≈ [√(2πX)] • (X/e)^X The answer is way too long and complicated to write here. You might try it once. My answer is (it is gigantic and it definitely could be wrong) : (-√(2π) xˣ√x)/eˣ + (√(2π)xˣ√x(2xlnx + 2x + 1))/2xeˣ
@mathevengers1131
@mathevengers1131 3 года назад
How about differentiating super cube root of x?
@MrMatthewliver
@MrMatthewliver 3 года назад
You mean the inverse of x^x^x ? It can be done through using a formula for differentiating inverse functions, after you manage to find a derivative of x^x^x :-)
@mathevengers1131
@mathevengers1131 3 года назад
@@MrMatthewliver yes
@penfriendz
@penfriendz 3 года назад
There are infinitely many continuous functions which can fit to the discrete factorial function. The gamma function is one of them, but what this video lacks is why the gamma function is the best choice.
@orkedar8786
@orkedar8786 2 года назад
Good point. The answer would be that it's meromorphic. There is only one such meromorphic function.
@dezutilo
@dezutilo 2 года назад
yes
@vascomanteigas9433
@vascomanteigas9433 Год назад
See the Bohr-Mollerup theorem. Gamma function are the unique function which respects. f(1) = 1 f(x+1) = x*f(x) , for all x>0 f(x) are log-convex for all x>0, which means that the second derivative of logarithm of f(x) are always positive.
@jandely8038
@jandely8038 2 года назад
Pls can you take indefinite integral of x! I need it
@baldski8866
@baldski8866 2 года назад
He asks at the end was that what u were expecting like yeah sure cuz i worked it out with my best friend and photomath lol
@kapilpathak4090
@kapilpathak4090 3 года назад
But what is the use of this as factorial is for only natural numbers that meanse it is not a cuntinous fucntion in any domain then how come it's differential can be calculated 🤔
@dominicellis1867
@dominicellis1867 5 месяцев назад
How do you solve that integral that comes from this derivative. I know I can change the variable t into W(u) but I don’t know how to integrate W. Where does the series for W lambert come from?
@minefan7
@minefan7 2 года назад
me: has an out loud realization about deriving factorials my 5th grade friend: bruuuuh
@subthermosphere
@subthermosphere 8 месяцев назад
Very great explanation!!
@johndoe7017
@johndoe7017 8 месяцев назад
Here o was thinking he’d use the Stirling Approximation for factorials and then differentiate that
@richard_larrain
@richard_larrain 3 года назад
i was thinking about this thing since i was 13 years old. THANKS
@umami0247
@umami0247 2 года назад
I'm fascinated by what this is don't understand any of it how it works or what it actually solves. But I am watching and again find it very interesting. Great video.
@lukostello
@lukostello 3 года назад
so much so fast! I cant learn math like this. I had to pause so often, and even then... sheesh. Looks like I need to brush up on partial derivatives.
@redasatisfaction9638
@redasatisfaction9638 3 года назад
U could have used the expression of 1 over gamma function where the euler-mascheroni constant shows up and derive from it the expression of the digamma function . Hence derivkng the formula of the derivative of x factorial ( WHAT THE FACTORIAL)
@MirzaAli-r5c
@MirzaAli-r5c 10 месяцев назад
Fantastic can you please explain. CArdano Method of solving Cubic equation
@cascounty
@cascounty Год назад
Looking for some help... Can anyone explain the answer to this question. "The local zoning ordinance requires that any property with impervious coverage that discharges more than 100,000 gallons of water in a 4-inch rainstorm must have a retention pond to handle the water. The proposed subject property will have 260,000 sf. of impervious surface. A cubic foot of water contains 7.48 gallons and retention ponds can hold no more that 500,000 gallons for safety reasons. There is no retention pond an the plan. What will this property discharge in a 4-inch rainstorm. Trying to use an HP C12 calculator... thank you.
@someuser257
@someuser257 2 года назад
My thought was that you may say (n/e)^n * sqrt(2пn) is equivalent to n! for big ns, so you may differentiate the latter
@KurdaHussein
@KurdaHussein 2 года назад
for differentiate an integrating with different variable don't you need to use Leibniz integral rule ?
@pedrosso0
@pedrosso0 3 года назад
Soooo before starting the video I got the idea of using the gamma function... I gave up xD.
@LearnwithTejeshwar
@LearnwithTejeshwar 3 года назад
I also started thinking that we can use gamma function for this
@pedrosso0
@pedrosso0 3 года назад
@@LearnwithTejeshwar I failed to use it though. But ehh, I got halfway xD
@christolo3637
@christolo3637 8 месяцев назад
I've got some news for you. The problem why diescrete funcions like the factorial have no derivative is not about continouity. In fact, every function defined on integers is continous. You can just check the definition. The problem is: the function is not defines on an open set, therefor, there is no good way a derivative can be defined
@hafizajiaziz8773
@hafizajiaziz8773 3 года назад
Derivative of a fractal curve. Something like the Weierstrass function
@ZipplyZane
@ZipplyZane 3 года назад
Going by the title alone: Seems like it would be fairly easy, since the gamma function (and thus the pi function) is defined as an integral. So just don't integrate it.
@p_square
@p_square 3 года назад
Can it be written in the form of digamma function?
@elimera23
@elimera23 3 года назад
How about the derivative of x^(1/x^(1/x^(1/x ... up to infinity?
@gardenmenuuu
@gardenmenuuu 2 года назад
Your animations are so neat,,is it manim or which software??
@Cjnw
@Cjnw 9 месяцев назад
e^x is always a sum of factorial reciprocals
@bapanbiswas4678
@bapanbiswas4678 3 года назад
Brilliant thinking🤔
@BriTheMathGuy
@BriTheMathGuy 3 года назад
Thanks! Have a great day!
@mike1024.
@mike1024. 2 года назад
A little playing around with actually trying to calculate that integral would have been desirable. I'm not saying it's easy, but perhaps a little something could be done to get closer to something more known.
@mdrifaturrahman2403
@mdrifaturrahman2403 3 года назад
When can we switch the derivatives and integral? Like there's dominated convergence theorem for Summation and Integration?
@arekkrolak6320
@arekkrolak6320 9 месяцев назад
Your first answer that derivative does not exist is probably the better one :)
@kroax9720
@kroax9720 3 года назад
Way easier than i thought
@BriTheMathGuy
@BriTheMathGuy 3 года назад
Glad you think so!
@kroax9720
@kroax9720 3 года назад
@@BriTheMathGuy i am a jee advanced aspirant for 2021 💪🤟 the problems there are really unexpected , anythung can come , your videos help in develovping that perspective 🤟
@Blaqjaqshellaq
@Blaqjaqshellaq 2 года назад
Is gamma the only continuous function that matches the factorial? Or can there be others?
@Blaqjaqshellaq
@Blaqjaqshellaq 2 года назад
@@mastery4667 Or gamma(x) + n*sin(m*x*pi), where n and m are any integers!
@andreaspapageorgiou2445
@andreaspapageorgiou2445 2 года назад
Thanks!
@linguafranca7834
@linguafranca7834 3 года назад
Easier than the expectations
@cheems1337
@cheems1337 2 года назад
You can actually find the factorial derivative without defining gamma function, just use the limit definition of derivative and you'll find that if f(x) = x! then f'(x) = f(x)*(f'(0) + H_x)
@anghme28ang11
@anghme28ang11 4 месяца назад
1:46 where does the x come from
@HoangTran-rg7nb
@HoangTran-rg7nb 7 месяцев назад
good solution and i learned gamma function
@sans1331
@sans1331 2 года назад
good one “Factorials _!_ “
@joshuanugentfitnessjourney3342
@joshuanugentfitnessjourney3342 3 года назад
It was exactly what I thought it would be, that math degree came in handy
@carultch
@carultch 3 года назад
Why is the gamma function offset from the factorial function by 1 unit in the x direction?
@hetsmiecht1029
@hetsmiecht1029 3 года назад
I don't know, but there's a thing called the pi function with the only difference being that the shift isn't present.
@hetsmiecht1029
@hetsmiecht1029 3 года назад
I don't know, but there's a thing called the pi function with the only difference being that the shift isn't present.
@shawnparvini8490
@shawnparvini8490 2 года назад
The derivative is: d/dx(x!) = Γ(x + 1) polygamma(0, x + 1).
8 месяцев назад
Muy buen video Genio!
@aperm8205
@aperm8205 2 года назад
i was thinking that u r going to use product rule lol 😂😂😂
@hetsmiecht1029
@hetsmiecht1029 3 года назад
I hate that the gamma function is more popular than the pi function (not the 3.14 pi). The formula of the pi function looks nicer as it doesn't have an x-1 but just an x, and pi(x) = x! and not (x-1)! as us the case for gamma(x). It's just nicer as an extension of the factorial function.
@charbeleid193
@charbeleid193 3 года назад
Try differentiating e^(phi*x) with respect to x over and over again. You'll get a pretty cool series
@chumblewumble2422
@chumblewumble2422 3 года назад
Are you sure
@thesecondderivative8967
@thesecondderivative8967 2 года назад
I understand why the Gamma function is x! (For discrete values) and as a result can be generalised to non-discrete values but how does one go about discovering the Gamma function?
@ВолодимирПроцишин
@ВолодимирПроцишин 8 месяцев назад
Wow, that was pretty easy), thanks
@whyyat3470
@whyyat3470 2 года назад
Needed to pause the video (several times) so my ears could catch their breath; remember, speed kills!!!
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