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Can someone help me? by Samuel Gagglechick - Sun, 08 Jan 2017 06:01:19 EST ID:QDezsc5/ No.15313 Ignore Report Reply Quick Reply
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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
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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

Watch my set please by Basil Fussletut - Fri, 18 Nov 2016 11:24:03 EST ID:FFd5rNZG No.15275 Ignore Report Reply Quick Reply
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Hey /math/, can you guys watch my set for me? I'll be right back.
10 posts and 6 images omitted. Click Reply to view.
Phineas Hinnerwill - Mon, 09 Jan 2017 22:47:18 EST ID:TdtLbn0v No.15318 Ignore Report Quick Reply
Are you certain of this
Barnaby Chindlestadging - Tue, 10 Jan 2017 16:28:23 EST ID:2HEwuEDh No.15319 Ignore Report Quick Reply
Yes, a set of all sets would contain itself. The set of all sets which do not contain themselves is paradoxical and we call this Russell's Paradox. The set of all sets cannot exist in naive set theory due to Cantor's Theorem, which says that you can't have a surjection from a set onto its power set. Since the set of all sets is its own power set and the identity map from that set to itself is a surjection, we have a genuine contradiction. Cue: type theory or wrangling with the category of all categories instead.
Polly Crazzlestodge - Thu, 12 Jan 2017 13:12:19 EST ID:zauFrAWR No.15321 Ignore Report Quick Reply

You don't absolutely have to use category theory or type theory to talk about that kind of collection. There are extensions of ZFC in which you can discuss proper classes like the collection of all objects that don't contain themselves, like Neumann-Bernays-Godel set theory. In New Foundations set theory there is powerful comprehension so the collection of all sets is indeed a set. It dodges Russel's paradox by specifying what kind of predicates are allowed to define sets.
Ebenezer Genkinnadge - Thu, 12 Jan 2017 14:29:49 EST ID:jD/Lrc1O No.15322 Ignore Report Quick Reply
Both of those systems you mention seem to be exploiting the idea of different "levels" of sets, which sounds like a type-theoretic way of dealing with the problem to me.
Augustus Bambleson - Thu, 12 Jan 2017 19:13:32 EST ID:zauFrAWR No.15323 Ignore Report Quick Reply

Yeah, there are different "types" of objects, but often times it's not apparent what a given object is. From this perspective you could make an argument that every set theory is a type theory, with just one type in consideration, which seems to obfuscate what distinguishes what is considered type theory as opposed to something else. In type theory you know exactly what sort of element you are dealing with, while this might not be the case in set theory.

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
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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
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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
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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
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What's the biggest number? by Nathaniel Sacklespear - Fri, 23 Sep 2016 09:54:08 EST ID:XssdERJk No.15209 Ignore Report Reply Quick Reply
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Assume we had all the possible methods of information storage in the universe and all the resources of the universe at our whimsical disposal.

What's the largest number we could put down in some kind of recording before we ran out of universe?

So I guess the core question I'm asking is what's the most compact way to write large numbers? Is there anything that beats out scientific notation? And what's the greatest extreme to which we could conceivably take this?
14 posts and 3 images omitted. Click Reply to view.
Walter Grandgold - Sun, 16 Oct 2016 23:18:00 EST ID:v1Le0MKE No.15247 Ignore Report Quick Reply
Educate yourself please. You know how to search.
Thomas Nickledale - Mon, 17 Oct 2016 01:26:18 EST ID:GRYB1TGG No.15248 Ignore Report Quick Reply
That doesn't answer my question at all.
Esther Fazzlechire - Wed, 19 Oct 2016 14:27:29 EST ID:3FW0gDej No.15249 Ignore Report Quick Reply
The size of a representation space (e.g. number of bits in the universe) just gives us the number of different values that can be represented, not the greatest value that can be represented. Arbitrarily large values can be represented with single bit if the encoder and decoder share a common domain containing just that value.
Cyril Faddlehood - Sat, 22 Oct 2016 23:13:07 EST ID:FnqCMFm+ No.15251 Ignore Report Quick Reply
The observable universe is basically a round bubble, and it includes everything we are able to... observe. What that's saying is that it is the furthest distance that we can see light coming from, or that particles of light are able to interact with and be measured by some medium from our location on earth. Outside of that bubble, the universe we are able to see no longer interacts with or receives any information from any matter or particles that might lie outside.

If you can't grasp what observable light entails, then the concept is above you. It honestly shouldn't require explanation, but hopefully what I wrote helps. If it doesn't, sorry nigga, you just aren't gonna get it.
Esther Pebberworth - Wed, 21 Dec 2016 08:37:41 EST ID:XNyHHSTC No.15297 Ignore Report Quick Reply
A bunch of cajoles!
24 is the highest number and thats it!


Linear Programming (Decision Mathematics Query) by Wesley Billingshit - Fri, 28 Oct 2016 13:53:23 EST ID:tyLg+ghU No.15252 Ignore Report Reply Quick Reply
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I am having difficulty formulating the following in terms of linear programming

A pig farmer uses at least 800kg of feed daily. The feed is a mix of corn and maize.
The special feed mixture must contain at least 25% protein and a maximum of 6% fibre

The composition of corn per kg is as follows:
Protein: 32g per kg ; Fibre; 27g per kg ; Price £ 0.3 per kg

The composition of maize per kg is as follows:
Protein: 360g per kg ; Fibre: 65g per kg ; Price £0.9 per kg

What is the minimum daily cost for the farmer, for food with at least 25% protein and max 6% fibre.
Comment too long. Click here to view the full text.
Beatrice Sushspear - Fri, 28 Oct 2016 16:54:06 EST ID:ZjFavw7f No.15253 Ignore Report Quick Reply
Without more information I would assume that you can take the amount of feed the farner needs to be exactly 800kg. Since there is no deal or discount for buying more corn or maize, any additional mass of feed will cost more money. As you are asked to minimize the cost to the farmer, you should always use the least mass possible.

Now it may be that you cannot minimize the cost and attain 800kg at the same time without buying some fraction of a kilogram of feed. This is probably why the question says "at least" 800kg. You will then need to take your answer and round up to the nearest integer if the feed is sold strictly by the kg and not just weighed en masse.
George Foffingworth - Mon, 31 Oct 2016 09:30:26 EST ID:tyLg+ghU No.15260 Ignore Report Quick Reply
Thank you, this was the only information provided so I shall do as formulated in OP. Thank you Beatrice Sushspear

muh math by Betsy Pushridge - Mon, 16 May 2016 20:04:48 EST ID:RHLOntyV No.15119 Ignore Report Reply Quick Reply
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Is mathematics a discovered (natural) or man-made phenomena?
Personally I think it's natural because it can precisely describe natural events and laws which those events must conform to.
Thoughts on this?
16 posts and 3 images omitted. Click Reply to view.
Eliza Chabberkotch - Tue, 13 Sep 2016 06:59:53 EST ID:9vmmdAPm No.15195 Ignore Report Quick Reply
literally the case.
Shitting Pittford - Sat, 24 Sep 2016 13:14:19 EST ID:NUcfB8E8 No.15213 Ignore Report Quick Reply
I guess you could take the number of classes he's supposed to have in the course of his carreer, calculate the chance of having 1 specific class/totalclasses * 1post/totalnoofposts (from the day of his first class until he actually had the specific class in case)

idk what I said looks confusing to me as well but I don't care enough it's just to get the discussion going
Celty !Iv58NJh.IE - Tue, 11 Oct 2016 20:20:20 EST ID:v3boz4eW No.15243 Ignore Report Quick Reply
That's reasonable.
*shit eating grin*
Mr. Schwitters - Sun, 16 Oct 2016 00:37:47 EST ID:xB0tAwHQ No.15244 Ignore Report Quick Reply
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It's both natural and man-made. Look at that documentary where Zizek is standing in a pile of garbage, and saying, "This is the most natural thing in the world!". Nature is man. Culture is nature. Man is not separate from nature. You can't take biology out of the environment from which the gene evolves.

Well, you hear "Time/space/maths doesn't exist, man" so often. But for whom does it not exist?

I perceive its existence. How do I perceive it? Through my nervous system. My nervous system is receiving billions of signals every second.

Luckily there is a brain there which categorizes those signals for me into distinct tracks based on what has been evolutionary fit. That way, when I see a bear in the forest, I don't take out my ruler and try to measure every hair on his body in order to determine if the bear is a threat. Automatically my brain detects a threat and different glands fire off hormones, etc. and I find some way to keep my pic-a-nick basket.

To get a real answer to this, you have to look at the nervous systems evolved through time, and how nervous systems react to the phenomenal world. We still have amoeba, reptile, mammal, etc. sense, and that affects our perception. The 'tracks' where we store imprints about previous threats/comforts determines our perception.

Euclidean geometry is only an explanation of the world as it relates to the perception of domesticated primates.

We wouldn't see space in 3D if our nervous systems were different. We wouldn't plot points in 3D space if our nervous systems were different. Phenomenal existence only appears as it does because we evolved through all of the other species in the environment and atmosphere that we did.

tl;dr perception is everything, practice magick and cast spells dude
Shitting Trotdale - Sat, 22 Oct 2016 10:53:25 EST ID:ussIY8P4 No.15250 Ignore Report Quick Reply
>We wouldn't plot points in 3D space if our nervous systems were different.

No, we would still plot points in space regardless of how we evolved. Euclidean geometry may be somehow ``favored'' by our biology because it is a good local approximation of the acutal curved space in which we live, but even if a creature evolved in a truly alien geomtery it would still make up the geometry we live in if it was intelligent, just like how we have made up infinite families of alien geometries that don't obviously correspond to our physical reality.

uhhh by Reuben Honeyhood - Sun, 25 Sep 2016 22:57:20 EST ID:Z131bdYa No.15216 Ignore Report Reply Quick Reply
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Can someone please explain to me what's happening here?
The idea of a fraction being made up of other fractions is already weird to me, but why is the answer just flipping them?
2 posts omitted. Click Reply to view.
Shit Goodshit - Mon, 26 Sep 2016 00:06:18 EST ID:XssdERJk No.15219 Ignore Report Quick Reply
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so to step back further, this general formula should apply at all times


Sorry for the triple post but I'm high and I got dyslexia, but that seems to be the relation between them
Cedric Dushtud - Mon, 26 Sep 2016 00:31:13 EST ID:cPdIZNc3 No.15220 Ignore Report Quick Reply
Here's a more intuitive example that I think makes this seem more obvious

0.5 / .025 = 2
which is... (in fraction form)
(1/2) / (1/4)
which is...
4 / 2 = 2
George Dezzlesudging - Fri, 07 Oct 2016 21:30:10 EST ID:GmQCz3Ds No.15238 Ignore Report Quick Reply
1/2 over 1/4. you flip 1 wrong fraction and multiply the 2 fractions together.

instead of .5 / .25 you're doing .5 times 4.
Lillian Daddlekeg - Sat, 08 Oct 2016 22:03:58 EST ID:A2j/BW/W No.15241 Ignore Report Quick Reply
(1/x)/(1/y) = 1*(1/x)/(1/y) = (xy/xy)*(1/x)/(1/y) = (xy/x)/(xy/y) = y/x

If you multiply the numerator and denominator of a fraction by the same value, the value of the fraction stays the same. Here you're just multiplying the top and bottom of the fraction by 2^5*7^2. The 2^5s cancel in the top and the 7^2 cancel in the bottom.
Ernest Cashfeck - Mon, 10 Oct 2016 10:20:43 EST ID:WotAVLKX No.15242 Ignore Report Quick Reply
lol man, dislexia? thats harecore

Help evaluate this integral? by Clara Bardwater - Sun, 25 Sep 2016 02:55:07 EST ID:os0KtXjb No.15214 Ignore Report Reply Quick Reply
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So I'm working on a Calc II assignment, and I'm stuck on a problem that asks for the volume of the infinitely long solid attached.

f(x) = xe^(-x^3), so I can prove that the integral converges. I'm a lazy cunt so I used Wolfram Alpha to evaluate the integral and the answer involves the gamma function, which puts solving it beyond the level of this class.

So is there a more obvious way to go about this problem, or did my prof. assign a problem that we can't actually do at this level?
1 posts omitted. Click Reply to view.
Thomas Mettingpeck - Sat, 01 Oct 2016 04:56:19 EST ID:6Tt8wvgx No.15234 Ignore Report Quick Reply
Have you tried bounding it by another function which you can prove converges?
Albert Snodman - Sun, 02 Oct 2016 16:30:45 EST ID:VNqFemsz No.15235 Ignore Report Quick Reply
I think they know that it converges but need an exact value for the intergral.
Hannah Wummerham - Wed, 05 Oct 2016 14:21:15 EST ID:QUTqUdS2 No.15236 Ignore Report Quick Reply
Yes you integrate by parts, no need for a Gamma function.
Charlotte Cunkinfoot - Fri, 07 Oct 2016 20:57:03 EST ID:q1podWFh No.15237 Ignore Report Quick Reply
I tried this. It only takes a u-substitution this way.

Also, the gamma function can be covered in a class at this level, although it isn't needed here.
Lillian Daddlekeg - Sat, 08 Oct 2016 21:13:04 EST ID:A2j/BW/W No.15240 Ignore Report Quick Reply
This. The integrand is pi*x^2*e^(-2x^3). Set u = -2x^3, the answer comes out to be pi/6.

10101011010101 by Betsy Fuckingway - Wed, 28 Sep 2016 20:51:12 EST ID:dJCwm4mq No.15225 Ignore Report Reply Quick Reply
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When u come onto the math board
Beatrice Subberbanks - Fri, 30 Sep 2016 16:50:22 EST ID:9fX9//hV No.15231 Ignore Report Quick Reply
What in the blue fuck are you talking about?
Charlotte Brezzlecheg - Fri, 30 Sep 2016 17:11:16 EST ID:ZD4TCLS2 No.15232 Ignore Report Quick Reply
I think that by posting a picture of the green vertical "code" from the movie The Matrix along with a binary string for a subject the OP is trying to indicate that they felt awed by the discussions taking place here.
Angus Blackbury - Fri, 30 Sep 2016 21:04:04 EST ID:sWygU/VW No.15233 Ignore Report Quick Reply
OP high as fuck

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