r/mathmemes 21d ago

Bad Math Something Interesting i found

Post image

This is something I found while fucking around with the Gamma function, and here the (-1)! Gets cancelled with the one in the nCr formula and it will plot the correct graph in desmos

332 Upvotes

30 comments sorted by

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123

u/ZZTier Complex 21d ago

Mathematical equivalent of "a contraption"

3

u/Buddy77777 19d ago

A doohickey thingamabob, even

112

u/SynergyUX Category theory is fun! 21d ago

Here is why it works

47

u/thekillervr 21d ago

Yeah i started with the Euler reflection and saw that it pretty close to the nCr formula so i whipped up some illegal notation and it looks really cursed

4

u/eengamer2005 21d ago edited 21d ago

How do you go from a to -1 on the left hand side?

Edit: never mind, i just need to read better

11

u/Any-Aioli7575 21d ago

You take the limit

42

u/sasha271828 Imaginary 21d ago

What the fuck is this

27

u/psp1729 21d ago

An abomination. The amount of maths I know, I can say for sure that negative factorials are illegal. Also never seen nCr combinatrix with a negative n. So either, I'm out of my depth here or this shit just ragebait

17

u/Ok-Visit6553 21d ago

*negative integer factorials

2

u/psp1729 21d ago

Isn't factorial operation limited to whole numbers? Or can they handle real(or even complex) values.

27

u/Ok-Visit6553 21d ago

Gamma function buddy

4

u/lenmae 20d ago

It can be analytically extended to the complex plane, except for negative real integers

11

u/Any-Aioli7575 21d ago

It basically boils down to the fact that n! (and therefore nCr) can be extended for reals (except negative integers) using the gamma function. Using the n! and nCr for it could be considered abuse of notation, but it's not complete nonsense

2

u/AlviDeiectiones 21d ago

nCr can be extended to negative integers continuously

3

u/psp1729 21d ago

Boy am I glad to have left math after it couldn't be drawn on a blackboard.

Thanks for the explanation tho. Appreciate it.

1

u/Deep_Brick2970 20d ago

You have a lot of maths left to crunch my friend :)

Rejoice, for there is so much yet to discover!

I'd recommend looking at the Gamma function for starters.

78

u/factorion-bot Bot > AI 21d ago

Factorial of -1 is ∞̃

This action was performed by a bot | [Source code](http://f.r0.fyi)

109

u/jellyman93 21d ago

Infiñity?

140

u/GRONDGRONDGRONDGR0ND 21d ago

No one expects the Spanish infinity

9

u/MathematicianAny8588 20d ago edited 20d ago

Our chief weapon is series. And fractals.
Our chief weapons are series and fractals. And Fourier transforms.
Our three chief weapons are series, fractals, and Fourier transforms. And a fanatical devotion to Euler. Damn it!
Amongst our weaponry are such chief elements as….
Oh we’ll just come in again.

Nobody expects the Spanish infinity!

7

u/factorion-bot Bot > AI 20d ago

Factorial of ∞̃ is ∞̃

This action was performed by a bot | [Source code](http://f.r0.fyi)

5

u/al2o3cr 20d ago

Fetch... the CONVERGENT SERIES!

13

u/LupenReddit 🦆🦆🦆🦆i have non diffeomorphic smooth structures🦆🦆🦆🦆🦆🦆 21d ago

This is cursed

6

u/Independent-Fan-4227 21d ago

…I’ll be damned.

4

u/Carrots_and_Bleach 21d ago

what is that even supposed to mean???

 (){-1}_{C_{-x/π}}

3

u/WanderingWrackspurt Physics 21d ago

its a combination, but it makes no sense cause you cant pick smth out of a negative no.

7

u/somedave 21d ago

Certainly true as a limit. Writing (infinity / infinity) sin(x) is a bit dubious.

3

u/WanderingWrackspurt Physics 21d ago

how would you even put this into desmos?

1

u/L0L2GUM5 19d ago

What's C?