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Can we have negative factorial? 

blackpenredpen
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We will figure out if we can do the factorial of -1/2 and the factorial of -1. We will be using the extension of factorial via the Pi function and the Gamma function. I will also give a summary at the end on when we can have negative factorials.
Pi & Gamma functions: • extending the factoria...
0^0 convention: • 0^0=1 is "seriesly" us... ,
negative factorial, • Can we have negative f...
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20 янв 2018

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Комментарии : 407   
@heliocentric1756
@heliocentric1756 6 лет назад
10:50 Why the inequality method doesn't work? Can't we solve it like this? For t between 0 to 1: e^t is smaller than or equal e, so 1/e^t is greater than or equal 1/e so 1/(te^t) is greater than or equal 1/(et) so the integral from 0 to 1 of 1/te^t diverge
@blackpenredpen
@blackpenredpen 6 лет назад
OMG! You are right! I forgot for that bound is from 0 to 1... This is what happens when I have to do two different types of improper integral back to back...
@Prxwler
@Prxwler 5 лет назад
Are you argentinian?
@udayadityabhattacharyya7496
@udayadityabhattacharyya7496 4 года назад
@@Prxwler ttrrrryyyrfi
@mujahidrao7278
@mujahidrao7278 Год назад
What is the Integration of {x+1/x}½ ? Please solve this problem.🙏🙏🙏
@Jacob-uy8ox
@Jacob-uy8ox 6 лет назад
try to do a complex factorial
@SEBithehiper945
@SEBithehiper945 5 месяцев назад
You can do it like this: When doing Π(z), plug in complex integration.
@Jeehd
@Jeehd 11 дней назад
💀
@sgiri2012
@sgiri2012 9 дней назад
​@@SEBithehiper945 How to actually calculate the negative number factorial without the intervention of gamma function plot. I want to plot (-1/3)!,(-2/3)!,(-5/3)!,... etc. i tried to solve by gamma integral. But didn't ended up in answer
@ramez2775
@ramez2775 6 лет назад
"How many ways can you arrange negative 1 apples?" ...
@alexwang982
@alexwang982 5 лет назад
R. 1
@yosefmacgruber1920
@yosefmacgruber1920 4 года назад
@@alexwang982 Oh really? Then n! for n
@alexwang982
@alexwang982 4 года назад
@@yosefmacgruber1920 gamma function, mate and we meet again!
@Fokalopoka
@Fokalopoka 4 года назад
@@alexwang982 using gamma function (-1)! diverges, and you cant even say that you can arrange it infinitely many ways, limit of x! as x->-1 doesnt exist
@Fokalopoka
@Fokalopoka 4 года назад
also gamma of -1 is 0!, remember your definitions
@ScottMaday
@ScottMaday 5 лет назад
*someone:* how many ways can you arrange negative half of a quarter *me:* square root of pi ways.
@arnavanand8037
@arnavanand8037 4 года назад
You are too uneducated mathematically for this channel
@ham1533
@ham1533 4 года назад
Robin Sailo I think he meant -1/2 of a quarter (coin)
@chaoticstorm8145
@chaoticstorm8145 4 года назад
@@arnavanand8037 Ohh and you're too educated for a joke?
@chaoticstorm8145
@chaoticstorm8145 4 года назад
@@arnavanand8037 get over yourself buddy
@sakuhoa
@sakuhoa 3 года назад
@@arnavanand8037 you too sit, have a nice day.
@donotlaughagain5093
@donotlaughagain5093 6 лет назад
factOREO!
@MichaelGrantPhD
@MichaelGrantPhD 2 года назад
As I said in your poll, this is a definition issue. There are of course well defined ways to extend the factorial function beyond the nonnegative integers. But the exclamation mark is reserved for that original, integral definition. It's unfortunate that the Gamma function is "off by one" or it would be easy to just use that and call it a day.
@GRBtutorials
@GRBtutorials 2 года назад
The Π function (mentioned in the video) is what you’re looking for, it’s the Γ function, but displaced by 1 unit: Π(x) = Γ(x+1).
@MichaelGrantPhD
@MichaelGrantPhD 2 года назад
@@GRBtutorials thank you!
@blackpenredpen
@blackpenredpen 6 лет назад
Why Gamma function? check out this page math.stackexchange.com/questions/1537/why-is-eulers-gamma-function-the-best-extension-of-the-factorial-function-to
@Neo-po2xw
@Neo-po2xw 6 лет назад
blackpenredpen so what's 0.5! ?
@sdsa007
@sdsa007 2 года назад
Thank you! This is very advanced for me , but I am so glad I can find answers to my math questions! Awesome!
@Filip6754
@Filip6754 6 лет назад
But can you do dis?
@PeterAuto1
@PeterAuto1 6 лет назад
Yes, cause e^t in the interval [0,1] is always less than e, so if you replace e^t with e the value gets smaller. and cause e is a constant it can be ignored entirely.
@azharhaque9
@azharhaque9 6 лет назад
Chvocht - thats how i found this video aswell, dont even know why i clicked on it
@quarkonium3795
@quarkonium3795 6 лет назад
Peter Auto r/wooosh
@thenixaless7493
@thenixaless7493 4 года назад
Yes *Leans Chair Backwards*
@greenpewdiepie4207
@greenpewdiepie4207 2 года назад
@@PeterAuto1 I know this was 4 years ago but woooooosh dude
@themsk9923
@themsk9923 2 года назад
You are literally bringing those questions which i always thought about 👍 thanks 😊
@factsheet4930
@factsheet4930 6 лет назад
Great this reminded me of the old questions we got back in elementary school where they asked things like: 2_2_2_2 = and you had to put signs in to make it equal as many numbers as you could usually like from 0 to 10 but now knowing whats -0.5! there is a cool question you can ask your friends 2_2_2_2=π and see if they can solve it! my solution is (-2^(-2)*2)!^2=π
@Jee2024IIT
@Jee2024IIT Год назад
Amazing
@ebz4125
@ebz4125 6 лет назад
Was wondering if you can make a video on the analytical continuation / poles of the gamma function? That'd be interesting.
@General12th
@General12th 6 лет назад
Yay! This makes so much sense!
@atrumluminarium
@atrumluminarium 6 лет назад
If I remember correctly, there's a neat trick where you can "extract" the divergences/poles (on the negative integers) by using the by-parts expansion of Γ. This gives Γ(x)=Γ(x-n)/(x(x-1)...(x-n)) or something along those lines (it has been a while since I did complex analysis so my memory is a bit hazy) where you end up with the first n poles along the negative integers in the denominator.
@jorgeeduardopereztasso6134
@jorgeeduardopereztasso6134 6 лет назад
I remember that in my Calculus exam my teacher put a question with that divergent integral... It took me like all the exam time to realize that cannot be solved. XD
@hritikworld9944
@hritikworld9944 6 лет назад
Jorge Eduardo Pérez Tasso in which exam bro
@jorgeeduardopereztasso6134
@jorgeeduardopereztasso6134 6 лет назад
In one of my College's exam @Hritik Rastogi
@tomatrix7525
@tomatrix7525 3 года назад
Extremely nice vid bprp
@nicholasleclerc1583
@nicholasleclerc1583 6 лет назад
14:11 “That I want my students to show...” OMG !! YOU HAVE STUDENTS !!!
@blackpenredpen
@blackpenredpen 6 лет назад
Nicholas Leclerc Yes
@bitcoinbuy
@bitcoinbuy 2 года назад
Kudos to those who understood this
@AbouTaim-Lille
@AbouTaim-Lille 2 года назад
f(t) = 1/e^t is absolutely continuous over any closed interval and it has a max and min in the [O, 1] so it is easy to compare the initial integral with that of 1/t multiplied by some certain constant which is Devergent.
@lill_m8
@lill_m8 2 года назад
Me: Can we have (-1)! at home? Mom: We have (-1)! at home. (-1)! at home: Undefined
@madhavstalks3925
@madhavstalks3925 6 лет назад
Loved video
@giladu.6551
@giladu.6551 6 лет назад
Keep doing what you're doing!
@yosefmacgruber1920
@yosefmacgruber1920 4 года назад
Do you live in ישראל (Israel)?
@madhavstalks3925
@madhavstalks3925 6 лет назад
Amazing stuff
@VSP4591
@VSP4591 3 года назад
Very ingenious. Congratulation.
@user-ns4et7de4z
@user-ns4et7de4z 3 года назад
Thank's very much
@williamwong03
@williamwong03 6 лет назад
you are fooking instant. recall and teach my math a lot~~~
@meryemnour9996
@meryemnour9996 3 года назад
Thank you
@michaelspence2508
@michaelspence2508 5 лет назад
You could also look at (-1)! as a sequence. Every time you subtract 1 you multiply by a larger value (in terms of absolute value) and change the sign. Roughly speaking it looks (vaguely) like the graph of x*sin(x) in that it approaches both infinity AND negative infinity which is why saying (-1)! = infinity is incorrect.
@pon1
@pon1 Год назад
If we treat the number line from negative infinity to positive infinity as a infinite circle then the undefined part is when both ends meet at infinity, I think they showed that each undefined part has its own infinity, I think there's some mathematical theory that uses that.
@VenTGM09
@VenTGM09 Год назад
Not necessarily. Remember, Infinity is a concept, so if you want, you can treat infinity like a number, but not exactly like one. Like the idea of ∞+n=∞ and 1/0≠+∞ or -∞, but instead is 1/0=±∞
@orngng
@orngng Год назад
@@VenTGM09 What do you mean "not necessarily", only to reply with something else that doesn't follow up on the original comment
@VenTGM09
@VenTGM09 Год назад
@@orngng did you even look at the last part :| Listen, (-1)! gets you a vertical asymtope as you can literally see in the graph of Π(x), and a vertical asymtope has the value of 1/0, which could possibly be ±∞. The original comment literally described a vertical asymtope is and why it's a problem to 1/0. Do YOU understand what the comment is even saying?
@VenTGM09
@VenTGM09 Год назад
@@pon1 That is called "Wheel Algebra", my friend.
@johi5951
@johi5951 6 лет назад
Ok ok i can do neg factorials... BUT CAN YOU DO THIS?
@joaomarcosdossantos7593
@joaomarcosdossantos7593 6 лет назад
Hi, I really enjoy your videos. Could you show something about the wau(or digamn) number. I saw it, and got curious. Thanks for your amazing videos here.
@dlevi67
@dlevi67 6 лет назад
It's all one. Check the date of the "wau" video.
@trueriver1950
@trueriver1950 6 лет назад
I prefer the second method, from 16:00 onwards - it is much more intuitively appealing If you insist on using the PI function we can still do the same Having already shown the relationship PI (n) = n.PI (n-1) in an earlier video, we can simply apply this result instead of repeating the Laplace integral again.
@yosefmacgruber1920
@yosefmacgruber1920 4 года назад
Would ∏(n) = n • ∏(n-1) be an improvement upon your syntax, or did I do it wrong in some way?
@Qoow8e1deDgikQ9m3ZG
@Qoow8e1deDgikQ9m3ZG 5 лет назад
instead of saying (-1)! is undefined or infinity, I think there is a need to put a strict and new definition to something like 1=0*infinity .... maybe something new symbol that is very super and like complex number i that avoid explain what is sqrt(-1)
@MrRyanroberson1
@MrRyanroberson1 6 лет назад
3:48 actually i made a comment similar to this in a peyam video. as a polynomial of degree 6 differentiated 7 times should get 0, if we differentiate 5.5 times to get a degree of 1/2, differentiate again for a power of -1/2, and finally half-differentiate then the 7th derivative of x^6 ~ 1/x
@Mephisto707
@Mephisto707 6 лет назад
Can you show us the graph of the Pi function?
@MathNerdGamer
@MathNerdGamer 5 лет назад
Take the Gamma function's graph and shift to the left by 1, because Pi(x) = Gamma(x+1).
@snakespeak
@snakespeak 6 лет назад
Brilliant!
@ARAVINDKUMAR-ug7gt
@ARAVINDKUMAR-ug7gt 4 года назад
Great sir
@igorzigmaker5785
@igorzigmaker5785 6 лет назад
I don't know why but hat scream at the very end just scared me so freaking much.
@blackpenredpen
@blackpenredpen 6 лет назад
sorry.... I think I forgot to lower the volume on that..
@homer4590
@homer4590 3 года назад
I don't understand all of this but it's fun to watch him get going on math
@purim_sakamoto
@purim_sakamoto 3 года назад
ふぇええ こうやって拡張できるのがガンマ関数の面白いところですねえ そして(-1)!がこれまた面白い
@cicik57
@cicik57 3 года назад
can you also view it as the series of sum ,and easy compare to known harmonic series and 1/n^2 series
@VikasKumar-jz5mv
@VikasKumar-jz5mv 5 лет назад
Sir U r great,👍👍👍💥💥💥💥
@flamingpaper7751
@flamingpaper7751 6 лет назад
Can you take the factorial of complex numbers, like i or 1+i? Or even quaternions like 1+i+j+k?
@bonkuto7679
@bonkuto7679 2 года назад
That would be cool just try and plug it in and see what happens
@wraithlordkoto
@wraithlordkoto 2 года назад
@@bonkuto7679 I don't think there is a meaningful or useful notion of what it means to raise a number to a quaternion exponent power
@The-Devils-Advocate
@The-Devils-Advocate 2 года назад
@@wraithlordkoto maybe not in today’s conditions of math and science
@wraithlordkoto
@wraithlordkoto 2 года назад
@@The-Devils-Advocate I dont remember what it means, but quaternion exponents are a thing actually
@The-Devils-Advocate
@The-Devils-Advocate 2 года назад
@@wraithlordkoto I meant that they might not be useful today, but later they could be, like imaginary numbers
@elliottmanley5182
@elliottmanley5182 6 лет назад
Have you thought about bringing your accessible approach to explaining derangements, subfactorials and the partial gamma function? When I first researched this, I find the appearance of e unexpected and delightful and the appearance of the nearest integer function completely counter intuitive. Now I've started looking at the analytic continuation of subfactorials and I find it counter intuitive in two ways. First that, as far as I can tell, it's defined everywhere, including negative integers and second that it maps real numbers into the complex plain.
@elliottmanley5182
@elliottmanley5182 6 лет назад
*plane. Oops.
@__fahim.__123
@__fahim.__123 10 месяцев назад
I used feynman's technique although its undefined its a pleasure to use that technique like its soo gud yk
@tejing2001
@tejing2001 5 лет назад
The Pi function has a singularity at each negative integer, but because those singularities are poles, not essential singularities, it is reasonable (so long as you take appropriate care) to say the value at those points is projective infinity in much the same way that other intuitive processes (like splitting up dy/dx and working with the dy and dx as individual values, or pretending the dirac delta is a function even though it isn't) are not only reasonable, but helpful, so long as you properly account for the caveats. That said, it is safer, if you're not confident of your ability to properly handle the caveats, to just say the value is undefined.
@haydenkarkainen1167
@haydenkarkainen1167 6 лет назад
Rip negative integers, thanks for the video!
@mathtips877
@mathtips877 3 года назад
DEAR SIR, I REQUEST YOU TO POST VIDEOS ON MULTIPLE INTEGRALS
@alexmeanin8049
@alexmeanin8049 Год назад
Cooool!
@thesardaunatv
@thesardaunatv 4 года назад
Thank you Mentor
@user-qb5gw7tc9e
@user-qb5gw7tc9e 4 года назад
15:58 i definitely heard "Ладно я шучу"
@thepipe6397
@thepipe6397 6 лет назад
That was a good clickbait tittle, i stoped immediately what i was doing.
@blackpenredpen
@blackpenredpen 6 лет назад
hehehe
@chrisrybak4961
@chrisrybak4961 2 года назад
Great! So, as 0! = 1! = 1 but n!
@protasov-by
@protasov-by 3 года назад
Hey! Maybe if factorial of (-1/2) i.e. -0.5! is sqrt(pi) then maybe if there is some rule as one factorial solution can be written as summ of other factorial solutions, then ! (-1) can be calculated and finally be defined from that?
@EHTom
@EHTom 6 лет назад
Can you use the squeeze theorem to find a value?
@odysseus9672
@odysseus9672 Год назад
(-1)! is undefined, but 1/(-1)! = 0 just fine. You can show this without resorting to the gamma function by considering the number of ways to write n symbols in a list of length k. That is given by n! / (n-k)!. First: how many ways are there to write the list when it has length n? n!, obviously, but that requires 0! = 1. Similarly, if k = 0 the formula gives 1, but that is also 0!. Put another way, there is one way to write an empty list, just put the grouping symbols (that avoids the philosophical worry over how to arrange 0 things). Second: how many ways are there to write the list when k > n? Zero ways, because you can never successfully write such a list, but that requires n!/(n-k)! = 0 for k > n.
@zubiiiiii_
@zubiiiiii_ 6 лет назад
I can barely understand anything but its so satysfying to watch lol
@linknero1
@linknero1 5 лет назад
so which for negative numbers are indetermined the factorial function?
@jowillll
@jowillll 5 лет назад
Love the accent ❤️
@factsheet4930
@factsheet4930 6 лет назад
I challenge you to make cool solutions to the indeterminate form 0^i with limits!
@randomviewer896
@randomviewer896 2 года назад
It's worth noting that as you approch (-1)! from the negative side, then it diverges to negative infinity too.
@VenTGM09
@VenTGM09 Год назад
Like I have said many times before, It is *_undefined_* due to *_definition issues._* A common solution used by the math community is ±∞ as it's own value instead of +∞ or -∞.
@veetaha
@veetaha 6 лет назад
Hey blackpenredpen. May I clarify something about your students? According to me, I study at the top 2 (or 1) university of Ukraine, and our students are so lazy that about 60% of all of them at my specialty do not pass calculus exam ('cause we have a strict tutor=)). So the question is: how many students pass your exams in average?
@VSP4591
@VSP4591 3 года назад
Excelent
@MultiJoan09
@MultiJoan09 5 лет назад
i have a question. pi(x) is a good function for factorials. But pi(x)*cos(2*pi*x) it's also a correct function for factorials. Why do use one and not the other one
@josearita6440
@josearita6440 6 лет назад
Hello! Can you make a video explaining this optimization word problem? I would really appreciate it! Love your videos btw! A woman in a rowboat 3 miles from the nearest point on a straight shore line wishes to reach the dock which is 4 miles farther down the shore. If she can sail at a rate of 6 miles per hour and run at a rate of 4 miles per hour, how should she proceed in order to reach the dock in the shortest amount of time? I can't figure this out! Thanks
@AhsimNreiziev
@AhsimNreiziev 6 лет назад
Trick question. If she sails -- although _rowing_ would be more consistent with her stated mode of transportation -- faster than she runs, and the shortest path is only rowing, then obviously taking the shortest path is not only the path of least distance, but also the path of least time. Rowing the *sqrt((3^2) + (2 ^ 2)) = 5 miles* (by Pythagoras' Theorem) at *6 miles / hour* would take her 50 minutes. All other paths are slower than that. There is a much more interesting type of problem that's similar than this, but it only works if the speed in the water -- or whatever travel medium the starting point is in -- is actually _slower_ than the one on the sand (or whatever type of medium the end point is in). It also only works if the end point is _not_ on the line that is the transition from one medium to the other (the shore in this case). Instead, it must be at least marginally "land-inwards", so to speak If you're interested, watch this video by VSauce. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-skvnj67YGmw.html The whole thing is brilliant and I definitely recommend watching the whole thing, but the type of problem I was talking is given an example at around the 6:25 mark (or maybe a few seconds after that -- it's the one with the mud and the road).
@Xnoob545
@Xnoob545 5 лет назад
James Grime (on numberphile) extended the function and it didn't work... i mean it kinda worked... i guess... -1! = 1÷0
@themanofiron785
@themanofiron785 3 года назад
Well the result is right...you still end up with infinity :)
@ffggddss
@ffggddss 4 года назад
Behavior of factorial in the vicinity of a negative integer: When n is a positive integer, and ε is an infinitesimal quantity, (-n + ε)! ~ (-1)¹⁻ⁿ·n!/ε An interesting plot to show this, is y = 1/x! It oscillates for x < 0, crossing the x-axis for each negative integer; the amplitude increases "factorially" as x becomes more negative. For x > 0, y > 0, and goes asymptotically to 0 as x increases toward ∞. y has a local maximum for x between 0 and 1. Fred
@andreamonteroso8586
@andreamonteroso8586 4 года назад
can you do Gamma(n+1/2) and Gamma(-n+1/2) formula? pls
@peanut12345
@peanut12345 5 лет назад
Yet sqrt -1 is Real, no -1! is UNREAL, Euler had Whiskey on Weekends.
@iloveevermore13
@iloveevermore13 2 года назад
4! 24 We divide 4 and 3! 6 We divide 3 and 2! 2 We divide 2 and 1! 1 We divide 1 and 0! 1 We divide "0" and -1! 1/0 nondefined We divide -1 and -2! -1/0 nondefined And for other negatife numbers x/0
@vietnambarca233gmail
@vietnambarca233gmail 6 лет назад
Please do a video on complex numbers factorials
@blackpenredpen
@blackpenredpen 6 лет назад
I will try!
@yosefmacgruber1920
@yosefmacgruber1920 4 года назад
@@blackpenredpen And what about quaternion factorials? Is there any such thing? Are quaternions the ultimate numbers?
@atharvaverma5013
@atharvaverma5013 5 лет назад
Blackpenredpen when I tried it on Hiper scientific calculator shows that (-1)! is -1
@mondherbouazizi4433
@mondherbouazizi4433 3 года назад
In the second part of the check, why not just say that (1/(t*e(t))) is always bigger than (1/t*e) {which is here 1/(t*e(1))} in the interval (0,1] and since the integral of {(1/t) * Constant} diverges, the other integral diverge as well? Edit: Recall, the integral of the function between these two values is the area beneath it.
@NekoChan_TV
@NekoChan_TV 2 года назад
So can we conclude that f : x => x! is defined on R/Z-* ?
@EAtheatreguy
@EAtheatreguy 2 года назад
So when I look up the gamma function on wikipedia, why is it defined for negative non-integers? This integral diverges for all exponents of t less than negative 1, right? So this integral can't be used to find those values. Is it just analytic continuation using the identity x!=(x+1)!/(x+1)?
@MysteryHendrik
@MysteryHendrik 2 года назад
Yes, it is analytic continuation using that identity.
@XESolar
@XESolar 6 лет назад
Complex factorials possible?
@davidrheault7896
@davidrheault7896 6 лет назад
Yes, GAMMA in complex analysis is a meromorphic function, it has poles with residues at negative integers, and you can compute the integral in all the positive complex domain (Re(z)>0 otherwise the integral in undefined). Beware the real part of z being negative though since you need the mirror to compute the analytic conitnuation, example , GAMMA (-3.15) = pi/sin(pi*(-3.15_)/GAMMA(4.15), same thing goes for any complex value with negative real part, you need to mirror into the original domain, GAMMA(z) = pi/sin(pi*z)/GAMMA(1-z)
@PhasmidTutorials
@PhasmidTutorials 6 лет назад
materiasacra
@davidrheault7896
@davidrheault7896 6 лет назад
Yes, since Re(z)=1 >0, the integral is convergent, GAMMA(1+i) = .4980156681-.1549498284*I
@dlevi67
@dlevi67 6 лет назад
Whatever the hell a "factorial" of a non-ordered field means. :-D
@alexwang982
@alexwang982 5 лет назад
reddit.com
@seemajois3263
@seemajois3263 6 лет назад
Can you please make a video on i factorial? !'i!'¡ looks good with Spanish exclaimation mark.😆
@adamkangoroo8475
@adamkangoroo8475 6 лет назад
Maybe make the next video about the derivative of factorial?
@davidrheault7896
@davidrheault7896 6 лет назад
Adam Kangoroo the derivative of the GAMMA function is called the digamma function and it is also meromorphic with the same poles
@fanamatakecick97
@fanamatakecick97 5 лет назад
Is it only the antiderivative of e^-1 that is a logarithm?
@user-vm6qx2tu3j
@user-vm6qx2tu3j 6 лет назад
Woohoo!
@rifaturrahman5779
@rifaturrahman5779 4 года назад
Wait can't we integrate e^(-t)/t by Feynman/Leibnitz rule?
@pizzy1992
@pizzy1992 3 года назад
Eventi with that technic it doesn't converge
@rubikonium9484
@rubikonium9484 2 года назад
3:48 that voice crack though
@Sans-bd3bn
@Sans-bd3bn 2 года назад
Me: hmmm lets open youtupe because i am tired of studying This man:
@assiddiq7360
@assiddiq7360 2 года назад
Where do I find the graph?
@koskovictor5095
@koskovictor5095 4 года назад
To blackpenredpen You analytically continue the integral so maybe maybe not using the integral for one partial gamma and sum for the other help get -1!. That's how mathematicians convergent for all values. Solve for f(n) being 1/(n!) and the solution for -1 is 0 thus defined. Also 1/0 the solution is unsigned ∞ and technically greater than ∞ so calling it ∞ is inaccurate. It's rather unsigned 1/0. Take the sum equation for for example sin and instead use it with sum replaced by integral from -∞ to ∞, averaging all multiple solutions in complex math of each integrand, and no dt. Now the negative coefficient multiply by f(n)=0 so zero out so 1/0 for result for factorials is valid.
@benwatkins10xd
@benwatkins10xd 3 года назад
Im doing my geograohy homework xD xxx
@kamoroso94
@kamoroso94 6 лет назад
So what is the domain of the factorial function?
@divergentmaths
@divergentmaths 2 года назад
(-1)! = Γ(0) = γ (the Euler-Mascheroni constant)
@cosimobaldi03
@cosimobaldi03 5 лет назад
Well if we know half! = root pi /2, then by a property of the gamma function (half - 1)! = half! /half = 2*half! = root pi.
@RafaxDRufus
@RafaxDRufus 6 лет назад
Steve, could you integrate sqrt(1+4x²)? I'd appreciate it so much
@kaszimidaczi
@kaszimidaczi 6 лет назад
Set tan(u)=2x, then sec^2(u)du=2dx. After that you end up with half of the integral of sec^3(u). You can find the solution to that on his channel. Then use the fact that u=arctan(2x).
@RafaxDRufus
@RafaxDRufus 6 лет назад
kaszimidaczi Oh thank you! I haven't though it could be possible with tangent. Thanks :D
@igorzigmaker5785
@igorzigmaker5785 6 лет назад
Simply set 2x = sh(u), then 2dx = ch(u) du, dx = ch(u)/2 du. Putting everything in your integral and knowing that 1 + sh^2(u) = ch^2(u) and ch(u) is always possible, you get ch(u) * ch(u)/2 du = 1/2 (ch(u))^2 du. After that use fact ch(u) = 1/2 (e^u + e^(-u)) and you'll get pretty simple integral with exponents.
@kaszimidaczi
@kaszimidaczi 6 лет назад
Rafa xD No problem :)
@obinnanwakwue5735
@obinnanwakwue5735 6 лет назад
His name is Steve?!
@rakshithgowda1606
@rakshithgowda1606 6 лет назад
Let g be a continuous function which is not differentiable at 0 and let g(0) = 8. If f(x) = x.g(x), then f(0)? A) 0 B) 4 C) 2 D) 8.
@aaronrashid2075
@aaronrashid2075 2 года назад
So this means that the factorial is undefined for all negative integers right?
@alexhancu969
@alexhancu969 6 лет назад
Can you try to do "(1/3)!"?
@ronitmandal7301
@ronitmandal7301 6 лет назад
But can you do this?!
@replicaacliper
@replicaacliper 6 лет назад
Its a meme you dip
@nutdanaiwongsomsak9162
@nutdanaiwongsomsak9162 3 года назад
3! = 1*2*3 = 6 2! = 3! /3 = 2 So that means (n-1)! = n!/n (-1)! = 0!/0= 1/0 = undefined
@billprovince8759
@billprovince8759 6 лет назад
While (-1)! is undefined, it seems that you should be able to show that lim(x --> -1+, x!) approaches +inf.
@dlevi67
@dlevi67 6 лет назад
Yes, but the same limit approached from the left approaches -inf, hence the "undefined".
@billprovince8759
@billprovince8759 6 лет назад
Agreed: There's a nice plot of the Gamma function (not the Pi function) at Wikipedia: en.wikipedia.org/wiki/Gamma_function
@billprovince8759
@billprovince8759 5 лет назад
@Gerben van Straaten Agreed: The value is undefined, because you reach different limits if you approach from left vs right. In fact, my comment shows that approaching -1 from above (i.e., x --> -1+), it approaches infinity.
@Cardgames4children
@Cardgames4children 6 лет назад
Gamma upsets me. The pi function is much more logical! What gives?!
@brandonklein1
@brandonklein1 6 лет назад
Also, putting in any n+1 to the gamma function... You'll find that it gives the same integral as the pi function by subtracting 1! The gamma function has a very useful property that gamma (x+1)=x gamma (x) which flirts very closely with the Reimann Zeta Function and a ton of other series in higher math
@atrumluminarium
@atrumluminarium 6 лет назад
Gamma function is usually much more convenient when studying the Riemann Zeta function
@tracyh5751
@tracyh5751 6 лет назад
gamma function also arises in statistics very naturally.
@CharlesPanigeo
@CharlesPanigeo 5 лет назад
@@tracyh5751 yep! Gamma distributions are useful for modeling continuous random variable distributions that are positively skewed. Also, other distributions like the chi squared distribution, and the exponinetial distribution are really special cases of the gamma distribution.
@MarcoMa210
@MarcoMa210 4 месяца назад
The gamma function is indeed very convenient for the riemann zeta function, but what i really don't get is people using it for calculating simple factorials, WHY??? You are doing more work when you could be using the capital pi function which is simpler.
@willpearson
@willpearson Год назад
I think it's a logical leap to say the pi function is equivalent to the factorial function. Just because the pi function happens to intersect with positive integers for the factorial function does not mean it *is* the factorial function. The factorial function is defined by using integers.
@TheLifeLaVita
@TheLifeLaVita 6 лет назад
(-1)! it’s easy: you can just use (-1)!=1/0 if you put it on the “recall” part it goes fine: 0!= 0 * (-1)! 1=0*(-1)! 1=0*1/0 (0 and 0 cancels out) 1=1 so 1/0 is a solution
@wojtek9395
@wojtek9395 6 лет назад
What about 1/n factorial f.e 1/3? I will try it on my own but I will probably fail. It may be e^t^3 but then I don't know what to do next, maybe it is related to higher dimensions.
@davidrheault7896
@davidrheault7896 6 лет назад
wo997 we don't usually use factorial but GAMMA function. And yes you can compute GAMMA(1/3) and by Euler reflection the other ones. This number is transcendental (PROVEN!) I guess what you mean is 1/3! = GAMMA 4/3
@himanshumallick2269
@himanshumallick2269 6 лет назад
Riemann Zeta function's integral expression involves gamma function. We know that Riemann Zeta function is defined everywhere in the complex plane (by analytic continuation), except for the line where Re(z)=1. Thus Zeta(-n) is defined (where n a positive integer). But when (-n) is plugged into the integral expression,the zeta function (LHS) is defined whereas RHS is undefined because gamma (-n) is undefined. How to resolve this problem????
@davidrheault7896
@davidrheault7896 6 лет назад
himanshu mallick zeta integral is only convergent for Re(z)>1 the same thing for GAMMA function (Re(z)>0). For any negative complex number I mean the real part you need to use the mirror for the analytic continuation (functional equation)
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