420chan now has a web-based IRC client available, right here
Leave these fields empty (spam trap):
You can leave this blank to post anonymously, or you can create a Tripcode by using the float Name#Password
A subject is required when posting a new thread
[*]Italic Text[/*]
[**]Bold Text[/**]
[~]Taimapedia Article[/~]
[%]Spoiler Text[/%]
>Highlight/Quote Text
[pre]Preformatted & Monospace text[/pre]
1. Numbered lists become ordered lists
* Bulleted lists become unordered lists


Community Updates

420chan now supports HTTPS! If you find any issues, you may report them in this thread
Maths is cool n shit by Straid Of Coolaphis - Fri, 28 Oct 2016 20:21:44 EST ID:g2pPf6fA No.15254 Ignore Report Reply Quick Reply
File: 1477700504974.jpg -(265201B / 258.99KB, 1403x1600) Thumbnail displayed, click image for full size. 265201
Can we have a maths party thread moderators? Because maths is cool and shit.
6 posts and 4 images omitted. Click Reply to view.
Fuck Tillingway - Tue, 21 Feb 2017 11:32:41 EST ID:j58znr37 No.15342 Ignore Report Quick Reply
Are you trying to start shit m8?

Category theory is the new set theory, it's fucking foundational.
Phyllis Fuvingbury - Tue, 07 Mar 2017 00:21:23 EST ID:vrOFV9fT No.15415 Ignore Report Quick Reply

Nobody cares about the Yoneda Lemma and it's NONSENSE to think that a monomorphism might not be injective!!! Trash category theory go home!!!!
Archie Cenderhood - Tue, 07 Mar 2017 10:03:55 EST ID:+wJbtIkG No.15416 Ignore Report Quick Reply
Have fun remembering fifteen different definitions of some uiversal construction which are all actually the same thing in different categories. Do you enjoy clogging your brain with extraneous nomenclature? (Please, no jokes that this is all that math is.)
Priscilla Brellydale - Tue, 14 Mar 2017 16:56:33 EST ID:0IIhzQOQ No.15417 Ignore Report Quick Reply
So what do you guys think about Hodge theory?
Is the hype over?
Shitting Huddlehan - Thu, 16 Mar 2017 14:35:45 EST ID:vrOFV9fT No.15421 Ignore Report Quick Reply

Homology is bullshit, cohomology is bullshit. The only reason people care about that stuff nowadays is for some data analysis purposes, so that means people are interested in actually computing homology groups of spaces rather than this deeper stuff. The only people that care are topology nerds.

Connection between graphs and differential equations by Jarvis Pessledale - Tue, 14 Mar 2017 17:17:53 EST ID:ueMHQ1BO No.15418 Ignore Report Reply Quick Reply
File: 1489526273324.jpg -(103964B / 101.53KB, 1024x768) Thumbnail displayed, click image for full size. 103964
I am curious if anyone knows how to represent differential equations as a graph? I acknowledge that that sounds absurd, but I am curious, I know you can represent a graph via tutte polynomial, so I figured it's not too much of a stretch.
Doris Billingforth - Tue, 14 Mar 2017 17:56:07 EST ID:zpTgkQCY No.15420 Ignore Report Quick Reply
1489528567485.gif -(281744B / 275.14KB, 305x294) Thumbnail displayed, click image for full size.
What do you want exactly? It's not absurd to ask for something as a graph since graphs, like most kinds of mathematical structures, are expressive enough to encode anything you want to do.

A given differential equation will give rise to a dynamical system right? Like if I give you a point the differential equation can tell me the derivative(s) at that point. These derivatives are instantaneous rates of change, but you can imagine for each point in your space following the corresponding tangent vector for a certain time t. If your space is over the reals you will obtain an uncountable family of uncountably infinite combinatorial graphs which vary with t. Maybe you can study the corresponding operators? It looks like the sequence tends to the identity but the way it changes might encode information about your solutions.

Restricted movement by Ian Cinderworth - Sun, 26 Feb 2017 18:58:58 EST ID:ncb8UBjg No.15412 Ignore Report Reply Quick Reply
File: 1488153538709.png -(45484B / 44.42KB, 1152x799) Thumbnail displayed, click image for full size. 45484
I like to ask here, because it's chill here and I the thought of citing /math/ on my bachelor's amuses me.

Pic illustrates a truck with a trailer, reversing in a clockwise circle. The axles are illustrated with a green wheel on the end of each radius.
The axle on the trailer can be steered.
Suppose the wheels on the trailer are turned slightly, creating a new radius and triangle shown in blue.
So after the truck has reversed for a bit, shown in pink, I think the trailer would move like shown, with the triangle intact, dragging it's point C along the "old" radius of the truck rear axle. (Old being the instance where the new angle of the trailer wheels were established)
My questions are: Do I reason correctly? and How does the angle B in the yellow triangle change, according to the trailer wheel angle, the trucks turning circle and distance traveled? You see, I'm interested in the point where yellow A an B are equal.

What do you guys think about this equation?? by equation - Thu, 16 Feb 2017 21:56:31 EST ID:3CQShUbt No.15337 Ignore Report Reply Quick Reply
File: 1487300191718.jpg -(376323B / 367.50KB, 2048x1536) Thumbnail displayed, click image for full size. 376323
Esther Dribbleforth - Fri, 17 Feb 2017 23:12:09 EST ID:A2j/BW/W No.15338 Ignore Report Quick Reply
>x = 0.0777...
>jk, x is infinity

Anyway, you fucked up the very first line. Should be 0.777... = 10x. From there, you can break up the lhs to get 0.7 + x = 10x. Subtract x from both sides: .7 = 9x. Divide by 9: x = 0.7/9 = 7/90. So 0.0777... = 7/90.
Beatrice Crenningmock - Sun, 19 Feb 2017 01:54:24 EST ID:A2j/BW/W No.15339 Ignore Report Quick Reply
And by "you" I mean whoever wrote that troll proof. I was under the impression it was your doing at first, but now I see you're just asking about it.

In that case, and looking at this with fresh eyes, I see that whoever wrote this is confusing (purposefully?) things like 0.7x with 0.7 + x.

0.7x = (7/10)(7/90) = (7*7)/(10*90) = 48/900 =

Whereas, 0.7 + x = 0.7 + 0.0777... = 0.777...

Or, 0.7 + x = 7/10 + 7/90 = 63/90 + 7/90 = 70/90 = 7/9

This confusing of addition with multiplication is the main theme of the "proof". The only things done correctly here are multiplying or dividing equations through by ten and the realization that a number subtracted from itself is zero (the number doesn't need to be infinity for this to work as is stated in the "proof").
Sidney Hummerwedge - Tue, 21 Feb 2017 00:04:06 EST ID:vrOFV9fT No.15340 Ignore Report Quick Reply

If you want to deal with things like 0.777 repeating it's best to use a symbol like a, rather than those fucking dots. Everything went wrong after the part in the rectangle in the attached image.
Fucking Grandville - Wed, 22 Feb 2017 00:08:02 EST ID:A2j/BW/W No.15343 Ignore Report Quick Reply
English use those dots instead of the vinculum. Chinese do too.

hex calc by CVF - Sun, 12 Feb 2017 00:53:25 EST ID:zOfzUnva No.15334 Ignore Report Reply Quick Reply
File: 1486878805691.jpg -(83985B / 82.02KB, 1280x720) Thumbnail displayed, click image for full size. 83985
good calculator that does hexadecimal? for school?
binary is a plus +
Basil Sinnerdedging - Mon, 13 Feb 2017 19:38:14 EST ID:A2j/BW/W No.15335 Ignore Report Quick Reply
Sophie Nennerstet - Mon, 13 Feb 2017 22:35:57 EST ID:ogPDtdlS No.15336 Ignore Report Quick Reply
If it's for a class use what they tell you. Otherwise use a smartphone, laptop, etc. It is what computers were originally made for, after all.

Top 10 favourite Integers by Colonel Badtouch - Fri, 04 Nov 2016 15:38:05 EST ID:9bYxsT36 No.15261 Ignore Report Reply Quick Reply
File: 1478288285194.jpg -(104652B / 102.20KB, 640x427) Thumbnail displayed, click image for full size. 104652
Hey guys what are some of your favourite integers? Here's my top 10:
10. 34,236
9. 8
8. 457,893 ( I bet some of you thought this would be higher!)
7. 43.
6. 6 (Imagine that!)
5. 240
4. 9000
3. 7,777,777
2. 7, 777,771
  1. 108
5 posts and 1 images omitted. Click Reply to view.
Jenny Gabberworth - Sat, 12 Nov 2016 08:43:59 EST ID:hLKFmGX4 No.15270 Ignore Report Quick Reply
You have good taste
Tom Waits - Sat, 12 Nov 2016 10:13:29 EST ID:jsJM/H7S No.15271 Ignore Report Quick Reply
1478963609990.jpg -(13347B / 13.03KB, 236x188) Thumbnail displayed, click image for full size.
Cornelius Brorrypick - Tue, 15 Nov 2016 19:41:50 EST ID:zOfzUnva No.15272 Ignore Report Quick Reply
1024 512 256 128 64 32 16 8 4 2 1
binary maths are fun
Sophie Clishville - Thu, 17 Nov 2016 23:18:33 EST ID:IoPw+j1r No.15274 Ignore Report Quick Reply
1479442713222.jpg -(25393B / 24.80KB, 220x295) Thumbnail displayed, click image for full size.


Every post in this thread starts with 15
Nigel Dartwater - Thu, 09 Feb 2017 18:17:46 EST ID:txB+9pVv No.15332 Ignore Report Quick Reply
1486682266851.jpg -(34208B / 33.41KB, 289x420) Thumbnail displayed, click image for full size.
10. 15625
9. 11
8. 222
7. 6
6. 50
5. 7
4. 800
3. 22222222222
2. 2919
  1. -7776

Calc by Hugh Jass - Tue, 31 Jan 2017 08:38:40 EST ID:Rhgh4/nK No.15328 Ignore Report Reply Quick Reply
File: 1485869920510.jpg -(10870B / 10.62KB, 489x93) Thumbnail displayed, click image for full size. 10870
  1. How do I set this problem up?
  2. Do I square the radical term to get rid of it?

The way my prof. writes these problems in a straight line is confusing. Thanks
Basil Gubberway - Tue, 31 Jan 2017 11:54:02 EST ID:A2j/BW/W No.15329 Ignore Report Quick Reply
This is simplification using order of operations, not calculus.







Comment too long. Click here to view the full text.

Can someone help me? by Samuel Gagglechick - Sun, 08 Jan 2017 06:01:19 EST ID:QDezsc5/ No.15313 Ignore Report Reply Quick Reply
File: 1483873279651.png -(36685B / 35.83KB, 1320x300) Thumbnail displayed, click image for full size. 36685
Jenny Tootbury - Sun, 08 Jan 2017 13:11:54 EST ID:a1cMDxo8 No.15314 Ignore Report Quick Reply
In general, you should make a sketch of the situation with all line segments and angles included, write those down and think about which of them you can calculate directly from what you're given, as well as your intermediate results.

In the present case, you know the lengths of all sides of the triangles PQR and PQX., and you want to calculate XR. What are some angles you can calculate? Is XR part of any interesting triangles, and is it possible to calculate some of the sides and angles in those triangles?
Cornelius Nittingpidge - Mon, 09 Jan 2017 06:00:40 EST ID:TYRFlDNG No.15317 Ignore Report Quick Reply
1483959640448.jpg -(18924B / 18.48KB, 320x320) Thumbnail displayed, click image for full size.
it's far bro
stay home
Charlotte Ficklepen - Wed, 11 Jan 2017 15:34:25 EST ID:A2j/BW/W No.15320 Ignore Report Quick Reply
Call angle QPX a and angle XPR b. Then you can use the law of cosines (LOC) to determine both a and a+b. Then subtract to get b. Then use LOC to find the length of XR using b. Sorry for the late reply.
Shitting Drussleford - Tue, 17 Jan 2017 19:32:16 EST ID:cHNY4zfv No.15325 Ignore Report Quick Reply
i know this shit seems retarded when you just doin geometry but try to really grasp the concepts cuz advanced math takes this triangle shit and makes some whole other crazy shit happen with circles till you got calc and beyond, all based on triangles, thats why pythagoras was a real OG nigga

Combine Data Sets Values Something by Doris Bemmlebanks - Mon, 02 Jan 2017 13:27:30 EST ID:RbgW2Zpy No.15304 Ignore Report Reply Quick Reply
File: 1483381650547.jpg -(51347B / 50.14KB, 156x518) Thumbnail displayed, click image for full size. 51347
Suppose youve got 2 data sets but they're in completely different units and not on the same scale. What operation could you apply to each row in order to get an idea of their combined result.
Sum? Average? Multiply?
2 posts omitted. Click Reply to view.
Nigel Hibblefutch - Fri, 06 Jan 2017 13:41:45 EST ID:tgwdoW8d No.15310 Ignore Report Quick Reply
Nah I just want to build a "score" from a bunch of different columns like this.

Maybe if you looked at the percentile of each row and averaged that.
Reuben Bunford - Sat, 07 Jan 2017 04:28:59 EST ID:tgwdoW8d No.15311 Ignore Report Quick Reply
I figured it out!
Calculated the percentile rank of each row relative to its column, then averaged all the ranks across! Fuck yeah!
break-a-bond !!D0XjIgKF - Sat, 07 Jan 2017 23:56:11 EST ID:tgwdoW8d No.15312 Ignore Report Quick Reply
This does not take into account weighting of each item if that matters at all.
So the forumula would become tedious
0.2*percentile1 + 0.8*percentile2
Then if you change that weighting from 20% -> 30% you're going to have to change every other weighting to add up to 1.
Eugene Gubberfuck - Sun, 08 Jan 2017 18:08:26 EST ID:/4S1D94J No.15316 Ignore Report Quick Reply
You cant build a score without context to what the data represents
Edwin Semmlebury - Sun, 22 Jan 2017 22:28:09 EST ID:C8IBIGCT No.15327 Ignore Report Quick Reply
Well he just did!
deal wit it

math for CS. by Fanny Gommerlirk - Sun, 07 Jun 2015 03:58:35 EST ID:8MLIP4Q3 No.14780 Ignore Report Reply Quick Reply
File: 1433663915621.jpg -(114090B / 111.42KB, 1021x682) Thumbnail displayed, click image for full size. 114090
I want to polish up some skills, specifically proof by induction, solving relations, and some calc. i think i know where to go for the calc (i learned it from the khan academy like 2 years ago and got a B+ in Calc II) but I can't find anything good for proof by induction or solving relations. i have some old lectures on my HDD but they aren't enough.

should I give in and hire a tutor? there is a top 10 stem school where I live and could get a tutor from physics, math, maybe CS, maybe another field's list but it's expensive.

pic unrelated
5 posts omitted. Click Reply to view.
Rebecca Bludgehene - Wed, 10 Jun 2015 20:50:36 EST ID:wkzayL5P No.14786 Ignore Report Quick Reply
MIT has math courses online free
Edwin Pittdale - Sat, 04 Jul 2015 04:12:10 EST ID:VtQDzEaN No.14811 Ignore Report Quick Reply
I appreciate the advice guys. Thank you!
Jack Wunderfuck - Sat, 15 Aug 2015 01:52:48 EST ID:PrRFulRY No.14859 Ignore Report Quick Reply
OP here again. I'll be studying calc (I have taken calc before and did fine) and discrete math this fall. im worried about the discrete math. my plan so far is to write down all proofs covered and make sure i learn each one and master it. i want to get close to 100% in this class. what tips to you guys have, beyond keeping at it and seeing prof/TAs regularly with questions?
Fuck Worthingway - Wed, 26 Aug 2015 23:04:36 EST ID:Dk8yywxc No.14867 Ignore Report Quick Reply

Make sure you do all of the assigned exercises. Try to do your own proof first on exercises, then look for a result on the internet. Hopefully you will be able to find many of the things you're asked to prove if you can't solve it yourself, but if you look at the result without trying it defeats the exercise of looking for a solution, which might screw you on the exam.

If you are ever lost with anything, work from the definitions and theorems you've used. Often you can solve a difficult problem by breaking something seemingly complicated into its parts, and then using the tools you have on the smaller pieces. The vast majority of professors will only ask you problems that they have previously exposed to you in class, homework, exercises, or at worst from the assigned textbook. If you feel you are struggling and have done all of the exercises and asked for correction from the professor, start doing the rest of the problems from the textbook and look for solutions.

Before you take any exam, at the very least read all of the exercises and questions in the textbook that you have been given. Oftentimes after being initially exposed to an idea without a solution and some time passes, we will be able to find a solution much more quickly than encountering problem without having seen it before.
Sidney Pittbury - Mon, 02 Jan 2017 17:51:19 EST ID:bM58eX3O No.15306 Ignore Report Quick Reply
fuk that, pick up a discrete math textbook. Then keep a copy of Advanced Calculus by Patrick Fitzpatrick around. Then whenever something troubles you about calc, look it up in that bby. It has a lot of goodies. In terms of CS numerical recipes contains most of the algorithms a person could ever want to use, code of them in C, and mathematical explanation of why they work.
Cheers and don't use it to build missiles u dingus,

Crazy Super Golden! by Barnaby Nicklewill - Wed, 28 Dec 2016 02:20:12 EST ID:RbgW2Zpy No.15300 Ignore Report Reply Quick Reply
File: 1482909612562.png -(8830B / 8.62KB, 254x223) Thumbnail displayed, click image for full size. 8830
How does it do it! Nobody knows!
Barnaby Nicklewill - Wed, 28 Dec 2016 02:21:59 EST ID:RbgW2Zpy No.15301 Ignore Report Quick Reply
Also has anyone worked with python's wolframalpha API thing?
Nell Murdway - Fri, 30 Dec 2016 20:27:46 EST ID:i+CEI2Ll No.15302 Ignore Report Quick Reply
See what I wonder is how does that mouth not just munch up the numbers? I mean it looks like their gonna fall right in.
Doris Bemmlebanks - Mon, 02 Jan 2017 13:28:20 EST ID:RbgW2Zpy No.15305 Ignore Report Quick Reply
These are the questions that keep mathematicians up at night.

TAKE THIS SURVEY SINCE YOU HAVE NOTHING BETTER TO DO by Clara Ducklock - Sat, 29 Oct 2016 17:03:32 EST ID:uIooC5VR No.15256 Ignore Report Reply Quick Reply
File: 1477775012355.jpg -(153642B / 150.04KB, 800x800) Thumbnail displayed, click image for full size. 153642

<<Last Pages Next>>
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Report Post
Please be descriptive with report notes,
this helps staff resolve issues quicker.