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Archived threads in /sci/ - Science & Math - 1385. page

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wtf is this? Math theory in pre-cal?

Question 1 (Answer before watching the video)

1. Contemplate on the word infinity. Think about what it represents. Now answer this question: do you think there are different sizes of infinity? Share your reasoning.

Questions 2 - 4 (Answer after watching the video).
https://www.youtube.com/watch?v=UPA3bwVVzGI

2. Give a 1- 2 sentence summary on Georg Cantor and his accomplishments.

3. Use your own words to define the terms "one-to-one", "rational", and "irrational".

4. Using the inequality symbol for less than (<), compare the following sets:

a. the set of rationals and the set of irrationals.

b. the set of decimals and the set of whole numbers.
21 posts and 2 images submitted.
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homework goes in >>>/hm/
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OP here. I think infinity is infinite because that is just the way it is and why it exist. There are not multiple sizes of infinity just like there is only one GOD. Honestly, I'm not even sure if infinity exist. It could just be a made up concept. GOD on the other hand is not. I know for sure imaginary numbers are crap because they are imaginary. They wouldn't call them that otherwise. OP out. Just wanted some opinions.
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>>8334272
That wasn't even funny. I'm not gay.

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>"If you're so smart, /sci/, why aren't you gold at an I(X)O?"
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>>8334251
>If you're so smart, woman, why do you have a X chromosome?
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>>8334761
Holy shit you're bad at basic biology
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>>8334761
fyi men have a x chromosome too

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Hi /sci/, brainlet here. Can you explain to me why i^i is a real number?

And why according to this page it can have other values?

https://www.math.hmc.edu/funfacts/ffiles/20013.3.shtml
12 posts and 1 images submitted.
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>>8334236
What part do you not understand?
They just use the Euler's formula and substitute x by pi/2 and then raise both sides by i.
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>>8334236
The problem lies within the question: How do you even define exponentiation of a general complex number? In the reals, you can easily define
[math] a^b := \exp(b \cdot \log(a)) [/math] for positive [math]a[/math] and arbitrary [math]b[/math]. The definition for general complex [math]a[/math] is a little involved, because the logarithm isn't uniquely defined if we allow complex numbers.
To see this in more detail, consider the basic example
[math]\exp(0) = 1 = \exp(2 \pi i) [/math]. We usually define [math]\log(1) = 0[/math], in line with the first equation here, but following this, [math]\log(1) = 2 \pi i[/math] would be equally sensible. It all comes down to choosing a sensible region, because we can't have multiple function values for the same argument, choosing a so called principal branch.
https://en.wikipedia.org/wiki/Principal_branch

So to come back to your original question:
Considering that [math] \exp( i \pi /2) = i [/math], we could choose our principal branch for the logarithm so that [math] \log(i) = i \pi/2 [/math]. Using our previous definition of complex exponentiation, we then find [math]i^i = \exp( i \cdot \log(i)) = \exp(i \cdot i \pi/2) = \exp(- \pi/2)[/math], which is a real number.
However, consider a different principal branch: For example, [math] \exp(i \pi/2 + 2 \pi i) = i [/math] is also completely viable, and would lead us to [math]i^i = \exp(- \pi/2 - 2 \pi)[/math], which is a different real number. And of course we could do this in infinitely many different ways, by adding different multiples of [math]2 \pi i[/math]. So our definition of complex exponentiation depends on the choice of branch, and thusly we won't have a well defined value of [math]i^i[/math] in general without any specification.

Let's see how broken my Tex is here now.
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>>8334265
wrong
>>>/b/

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if we human were wired better for logical thinking, a smarter race so to say, would we be happier or off worse? discuss
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>>8334201
>if we human were wired better for logical thinking, a smarter race so to say, would we be happier or off worse? discuss

Intelligence in the general population is bad for buisiness.
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we are wired for logical thinking, people just lack the motivation to apply it
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>>8334201
There are plenty of smart people that do awful things. We need more morality, not more intelligence.

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Why did this article trigger /sci/ so much the last time it was posted?

>https://aeon.co/essays/your-brain-does-not-process-information-and-it-is-not-a-computer

We should stop comparing the human brain with the current technological breakthroughs. The model could help explain some parts of human intelligence but in the end it will always fail, for it's way too simplistic.

And worse of all it will probably lead to some shitty sci-fi novels.
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The article is wrong in all possible ways.

The brain does store and retrieve memories.
It moves information around for processing and storage. Memories are processed and transformed before they're stored.

And you can find Beethoven’s 5th Symphony in the brain of some people, certainly including Beethoven.

The article is written by a psychologist that had his feelings hurt when the human psyche moved from some abstract concept to a more concrete model.
I'm sorry that he doesn't like it, but this is the reality.
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>>8334199
>The model could help explain some parts of human intelligence but in the end it will always fail, for it's way too simplistic.

It's actually abstract enough to work.
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Not a peer-reviewed scientific journal?
Into the trash.
Why is /sci/ so fulled of /x/ and /pol/ these days?
At least when /his/ was here they avoided using fallacies.

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So far our efforts have been focused on the general projective plane. While this has done us well so far, there are reasons we may want to change our focus, if only for a while.

Firstly, recall we based our axioms on observations of the Euclidean plane. Furthermore, the real projective plane is basically the Euclidean plane with a line at infinity. However, the Euclidean plane is just the two dimensional version of Euclidean geometry. So far, we haven't found a way to generalize projective planes in the same way, and it would be interesting to find out how, if possible.

Secondly, while we have built up a good collection of simple theorems from the plane axioms, we can't get much further with the plane axioms alone. The problem is that while the plane axioms ensure the presence of projectivities, they cannot really control their behaviour, and as such there is not much that can be proven about projectivities or projective planes from the plane axioms alone. We thus seek a natural restriction on projective planes that will allow us to 'tame' the projectivities. This control will payoff in the existence of complex structure and sophisticated tools that otherwise may be absent.

To get an idea of how to construct 'n-dimensional' analogues of projective space, we shall look at the Axioms 1-6 one by one.

Axioms 1 and 2, not only are both true in Euclidean and projective planes, but also in every Euclidean space, so that so it seems that these two axioms should remain unchanged. Note in particular this means that Theorems 1.1 and 1.2 also apply.

Axiom 3 is tricky, so we leave that for now.

As for Axioms 4-6, there is nothing wrong with Axiom 4, but for full generality, we also want projective analogs of Euclidean spaces of dimension lower than two. Axioms 5 and 6 are incompatible with this, so they must go.

That leaves us with Axioms 1, 2, and 4, but we still need to deal with Axiom 3. That will be done in the next post.
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Section 0(>>8266952) text: http://pastebin.com/50w9MYjD
Section 1 text(>>8282778): http://pastebin.com/fMdRzhTf
Section 2 text(>>8317513): http://pastebin.com/GfdvBDML

Definitions and notations: https://www.dropbox.com/s/ia4m7s0fy59z9jv
Axioms, Theorems, and other statements: https://www.dropbox.com/s/6ch0btu3adiz2ob
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>muh axioms
into the trash
>>
In Euclidean space dimensions 3 and higher, there are three relevant cases for two distinct lines:

-intersecting
-parallel
-skew(non-coplanar)

Axiom 3 doesn't have to deal with the skew case, so our task is to show how to correctly treat the skew case projectively. Recall that one of the arguments for the line at 'infinity' was continuity. If you 'nudge' a pair of parallel lines so they aren't skew, then they intersect at a point 'far away', which justifies the idea that they intersect 'at infinity'. On the other hand a 'nudge' to a pair of skew lines almost always keeps them skew. This suggests the correct way to handle projective 'skew' lines is to not let them meet.

This means Axiom 3 must be replaced by a statement like 'All coplanar lines meet.'. The problem with this statement as it is is that it make reference to a plane and thus the plane axioms. Since this is supposed to be a generalization of projective planes, this situation is not ideal.

To resolve this we look back at Euclidean space. Here three distinct points are always coplanar, but not so for four points. Thus, we would like our axiom to involve four distinct points. A way to ensure that the points are coplanar is to have the line through two of the points be coplanar to the line through the other two points. This then ensures all pairs of lines incident to two of the four points are coplanar.

That then suggests the following axiom in the projective case:

Axiom 3-(Veblen-Young axiom): Given 4 distinct points a, b, c, and d, if the line through a and b meets the line through c and d, then the line through a and c meets the line through b and d.

Using our point and line naming conventions, we can restate the axiom as follows:

'Given four distinct points a, b, c, and d, if [ab][cd] exists, so does [ac][bd].'

With the axioms now settled, we can define some important terms in the next post.

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So what happens if a scientist (let's say a faculty member at a university) suddenly has a brilliant idea, for example a possible solution to a Big Problem in his field and an experiment to test it, but doing so is not among the objectives of any of his current grants?

Does he write a grant proposal at that point? That sounds like a huge delay which would make it very likely someone else will publish the same thing first.

Do academics have faster means of securing smaller amounts of funding for such things?
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>>8334131
No, your idea dies with you because nobody will believe and/or fund you, unless you're very lucky.
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>>8334143
Simple and true.

Unless you manage to acquire a freak grant that allows you to do whatever the fuck you want (e.g. Bill Gates believing in your 'vision'), you ALWAYS word your grant in such a way that you maximise the chances of success. This means that the funding call is already limiting what you can or can not do. Sure, there's always a bit of wiggle-room and most scientists like to invest a tiny portion of their money into their pet projects, but other than that - progress in tiny steps.
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>>8334131
Your ideas are actually shitty, you just haven't thought about them enough.

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are trees vegetables?
11 posts and 2 images submitted.
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>>8334080
Look it up, then swallow some rat poison.
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>>8334080
I think you're a vegetable anon
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>>8334080
somebody's never eaten bark before

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Is it worth getting a bachelor's degree in or should I switch my major before its too late
15 posts and 1 images submitted.
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>>8333971
Gonna guess, you entered physics because of the money

Just switch to whatever you like, dumb frogposter
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>>8333982
Why would he enter physics for money? If he wanted money he would enter something like petroleum engineering.
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>>8333982
I chose to enter physics because I like it

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>mfw my forum built from scratch works

Hey /sci/, /b/fag here.

I could use some testers. No need to filter yourselves, go all out.

http://dmanufacture.com/d-general.php

Only requirement is a pic + name.
13 posts and 1 images submitted.
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Cant register bruh
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>>8333833

Post pic for reason? I put rules but theres a chance I fucked it up.
>>
The username must be >=6 characters, right?

HOW ABOUT YOU WRITE THAT BELOW THE REGISTRATION FORM?

Also, this is /sci/, not /g/

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What do you think about pandering to funding bodies?

for instance, your research proposal is highly likely to be funded if it involves something cute, endangered, economically/ecologically important, or involves climate change.

Is it disingenuous to purposely try to include one or more of these things in your subject matter ?

I think its a fucking necessity; funding doesn't just pop out of nowhere, and the idea that a government or enterprise is going to fund you to research something because you think its cool or feel emotionally attached to it is child-like

Others disagree

What do you think, /sci/ ?
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>>8333754
I have very good concept about research in my field but i have no idea who to talk to since everything is about knowing the right people which I dont.
I dont even know who to pander to lmao
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>>8333758

Assuming you have graduated you should know how this works.

When I say pandering I'm talking about institutions, not individual people.

Do you not understand how funding works in STEM
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>>8333766
>Do you not understand how funding works in STEM
No not really.
I know im retarded

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I 'm in the middle of a funeral, I want to say something about death , I advise something fast to read?
26 posts and 3 images submitted.
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read that one monologue from Hamlet
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Who the fuck checks 4chan during a funeral?
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>>8333751

What the fuck did you just fucking say about me, you little bitch? I’ll have you know I graduated top of my class in the Navy Seals, and I’ve been involved in numerous secret raids on Al-Quaeda, and I have over 300 confirmed kills. I am trained in gorilla warfare and I’m the top sniper in the entire US armed forces. You are nothing to me but just another target. I will wipe you the fuck out with precision the likes of which has never been seen before on this Earth, mark my fucking words. You think you can get away with saying that shit to me over the Internet? Think again, fucker. As we speak I am contacting my secret network of spies across the USA and your IP is being traced right now so you better prepare for the storm, maggot. The storm that wipes out the pathetic little thing you call your life. You’re fucking dead, kid. I can be anywhere, anytime, and I can kill you in over seven hundred ways, and that’s just with my bare hands. Not only am I extensively trained in unarmed combat, but I have access to the entire arsenal of the United States Marine Corps and I will use it to its full extent to wipe your miserable ass off the face of the continent, you little shit. If only you could have known what unholy retribution your little “clever” comment was about to bring down upon you, maybe you would have held your fucking tongue. But you couldn’t, you didn’t, and now you’re paying the price, you goddamn idiot. I will shit fury all over you and you will drown in it. You’re fucking dead, kiddo.

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I almost failed highschool math and the teacher told me I would never amount to anything. I have holes in my foundation but I have been practicing for a couple months since I would like to go into math at uni. Any advice? How can I go from full retard in math to 4.0 math major?
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>>8333698
Hard work, passion, it may not be enough for 4.0 but with 4/5 hours of work a day it will get better every day
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>>8333701
I've currently been doing pic related. I haven't seen drastic improvement I usually glide through questions no problem but get stuck for hours on one due to holes in my math foundation. I want to know how to fill in these holes but I don't know what I don't konw
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>>8333698

old highschool maths teacher told me i'd never amount to anything

now i'm starting my post-grad thesis, and that bitch is fuckin' dead

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Is this possible /sci/?

>water of the reservoir generates electricity
>the water at the bottom evaporates
>it has to ascend a tunnel because there is for example a glas roof on the water.
>it condensates in the cool mountain and flows again in the reservoir.
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Sure. You could get a few drops back into the reservoir by the time it empties completely.
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>>8333588
Weeell... This is basically how the atmosphere works, so...
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>>8333599
I assume he meant an isolated system. A reservoir that doesn't refill from groundwater.

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>be me
>compsci brainlet
>have a grafix course
>naturally we get some linear algebra
>time to git gud
>endterm has basic questions like
>calculate the determinant of this simple 3x2 matrix
>add these 2 matrices

It felt really weird answering these questions. On one hand, it's ez points, on the other hand it's just almost insulting to have such questions on an academic institution. The upside is that the practicals were high level, so maybe thats why there was little emphasis on theory, but still.

Their excuse with lame exams is that they have a lot of students and too few professors/teachers. So they come up with simple (but often trick) questions and multiple choice.

Am i exagerating, or is this one of the reasons why compsci is mocked so much by mathfags?
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>>8333574
>determinant of 3x2 matrix

Sounds like you failed.
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>>8333580
oops was looking at the wrong matrix/question
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>>8333580

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